From 24a3813c630ee99a29637f138c69f71e509805a7 Mon Sep 17 00:00:00 2001
From: Menghuan1918 <menghuan2003@outlook.com>
Date: Mon, 31 Aug 2026 01:31:22 +0800
Subject: [PATCH] =?UTF-8?q?feat!:=20=E5=90=88=E5=B9=B6=20Git=20=E9=9D=A2?=
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MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

在 PR #471（file-trace）基础上的演进：

- 合并 tab：git tab（id 保留，兼容持久化布局）升级为「文件变动」双视角
  tab——Git 视角（原 GitView 全部能力：staged/unstaged/提交/历史/worktree·
  子仓库选择/右键菜单/确认弹窗）+ 本轮文件视角（原 file-trace：会话事件
  日志实时折叠的模型读写编辑记录，按文件分组、新增类型筛选 chips、相对
  时间）；file-trace tab 移除（未随任何版本发布）。
- 统一 diff 组件：新 src/client/diff/ 模块（rows.ts 引擎 + DiffRows/
  DiffFiles 渲染器 + highlight.ts 语法着色）——git diff 与会话操作 diff
  共用一套渲染：mod 改写配对（del-run/add-run 对半标蓝）、行内字符级
  高亮（修复了旧实现旧侧失配不高亮的问题，改为行对象身份键）、上下文
  hunk 折叠、git hunk 间未输出区间按行号范围生成不可展开折叠、语法着色
  色相落位 diff 三色空档、+n −m 统计 chips、行底色 tint；DiffTab 改用
  该栈（git diff tab 从此也有高亮）。
- 交互：两视角共用底部可拖拽预览面板（点击文件/提交/操作即预览，不再
  直接开 diff tab；面板可刷新、可键盘/拖拽调高、git 目标可一键展开为
  独立 diff tab）；视角选择与面板高度持久化在 tab.meta；git 行 XY 徽章
  按状态字母着色；选中行高亮。
- i18n：fileTrace* 十键重命名为 changes* 前缀，git 键值更新为「文件
  变动」，新增 7 键（视角/筛选/面板操作），全部 21 个词典同步。
- 结构：src/client/changes/（ChangesTab/GitLens/SessionLens/DiffPane/
  ops）+ src/client/diff/；GitView/DiffView/filetrace/ 删除；git 样式
  从 sidebar.module.css 迁至 changes.module.css。
- 测试：builtins 8→7（git tab 承接 badge pin）、diff-rows（unified
  转换/mod 配对/间隙折叠/统计）、changes-tab（壳交互 jsdom）、
  diff-files-collapse（原 DiffView 折叠行为钉住）、changes-ops（原
  filetrace 数据层）、git-view-worktree 迁移至 GitLens；全量 1122 通过。
- 文档：README ×2 功能矩阵合并、external-plugin-guide §4.4 与内置清单
  7 tab、mount e2e 菜单标题同步。
---
 README.md                                     |   7 +-
 README_EN.md                                  |   7 +-
 docs/external-plugin-guide.md                 |   8 +-
 src/client/DiffTab.tsx                        |  13 +-
 src/client/DiffView.tsx                       | 305 -----------
 src/client/FenceErrorNotice.tsx               |   2 +-
 src/client/TabBar.tsx                         |   2 +-
 src/client/builtins/tabs.tsx                  |  53 +-
 src/client/changes/ChangesTab.tsx             | 127 +++++
 src/client/changes/DiffPane.tsx               | 313 ++++++++++++
 .../{GitView.tsx => changes/GitLens.tsx}      | 140 +++---
 src/client/changes/SessionLens.tsx            | 127 +++++
 src/client/changes/changes.module.css         | 386 ++++++++++++++
 src/client/{filetrace => changes}/ops.ts      |  12 +-
 src/client/diff/DiffFiles.tsx                 | 122 +++++
 src/client/diff/DiffRows.tsx                  | 270 ++++++++++
 src/client/diff/diff.module.css               |  81 +++
 src/client/{filetrace => diff}/highlight.ts   |  15 +-
 src/client/diff/rows.ts                       | 473 ++++++++++++++++++
 src/client/filetrace/FileTraceTab.tsx         | 336 -------------
 src/client/filetrace/diff.ts                  | 257 ----------
 src/client/filetrace/filetrace.module.css     |  76 ---
 src/client/locales-ar.ts                      |  29 +-
 src/client/locales-de.ts                      |  29 +-
 src/client/locales-fr.ts                      |  27 +-
 src/client/locales-hi.ts                      |  29 +-
 src/client/locales-id.ts                      |  29 +-
 src/client/locales-it.ts                      |  27 +-
 src/client/locales-ja.ts                      |  29 +-
 src/client/locales-ko.ts                      |  29 +-
 src/client/locales-nl.ts                      |  29 +-
 src/client/locales-pl.ts                      |  29 +-
 src/client/locales-pt.ts                      |  27 +-
 src/client/locales-ru.ts                      |  29 +-
 src/client/locales-sv.ts                      |  29 +-
 src/client/locales-th.ts                      |  29 +-
 src/client/locales-tr.ts                      |  29 +-
 src/client/locales-vi.ts                      |  29 +-
 src/client/locales-zh-HK.ts                   |  29 +-
 src/client/locales-zh-MO.ts                   |  29 +-
 src/client/locales-zh-TW.ts                   |  29 +-
 src/client/locales.ts                         |  56 ++-
 src/client/paths.ts                           |   9 +
 src/client/sidebar.module.css                 | 420 +---------------
 tests/builtins.spec.ts                        |  21 +-
 ...{filetrace.spec.ts => changes-ops.spec.ts} |  12 +-
 tests/changes-tab.spec.tsx                    | 133 +++++
 ....spec.tsx => diff-files-collapse.spec.tsx} |   6 +-
 tests/diff-rows.spec.ts                       | 123 +++++
 tests/e2e/mount.e2e.ts                        |   4 +-
 tests/git-view-worktree.spec.tsx              |  14 +-
 tests/git.spec.ts                             |   2 +-
 tests/locales.spec.ts                         |   8 +-
 53 files changed, 2693 insertions(+), 1792 deletions(-)
 delete mode 100644 src/client/DiffView.tsx
 create mode 100644 src/client/changes/ChangesTab.tsx
 create mode 100644 src/client/changes/DiffPane.tsx
 rename src/client/{GitView.tsx => changes/GitLens.tsx} (88%)
 create mode 100644 src/client/changes/SessionLens.tsx
 create mode 100644 src/client/changes/changes.module.css
 rename src/client/{filetrace => changes}/ops.ts (95%)
 create mode 100644 src/client/diff/DiffFiles.tsx
 create mode 100644 src/client/diff/DiffRows.tsx
 create mode 100644 src/client/diff/diff.module.css
 rename src/client/{filetrace => diff}/highlight.ts (96%)
 create mode 100644 src/client/diff/rows.ts
 delete mode 100644 src/client/filetrace/FileTraceTab.tsx
 delete mode 100644 src/client/filetrace/diff.ts
 delete mode 100644 src/client/filetrace/filetrace.module.css
 rename tests/{filetrace.spec.ts => changes-ops.spec.ts} (93%)
 create mode 100644 tests/changes-tab.spec.tsx
 rename tests/{diff-view-collapse.spec.tsx => diff-files-collapse.spec.tsx} (91%)
 create mode 100644 tests/diff-rows.spec.ts

diff --git a/README.md b/README.md
index 42b76c8..085367b 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@
   <a href="https://dshfind.com/zh/plugins/omdsh-dev/DSH-better-sidebar?ref=badge"><img alt="dshfind" src="https://dshfind.com/api/badge/omdsh-dev/DSH-better-sidebar?lang=zh" /></a><br /><br />
   <a href="https://www.npmjs.com/package/@deepseek-ai/dsh?activeTab=versions"><img alt="支持的 DSH 版本（v0.18.0-alpha.0 alpha 通道）：0.1.2-alpha.2" src="https://img.shields.io/badge/DSH-0.1.2--alpha.2_(alpha%20%E9%80%9A%E9%81%93)-4d6bfe" /></a>
   <a href="https://github.com/topics/dsh-better-sidebar"><img alt="插件生态：GitHub topic dsh-better-sidebar" src="https://img.shields.io/badge/%E6%8F%92%E4%BB%B6%E7%94%9F%E6%80%81-topic%20dsh--better--sidebar-4d6bfe" /></a><br /><br />
-  <img alt="文件管理" src="https://img.shields.io/badge/-文件管理-4d6bfe" /> <img alt="编辑预览" src="https://img.shields.io/badge/-编辑预览-4d6bfe" /> <img alt="内嵌浏览器" src="https://img.shields.io/badge/-内嵌浏览器-4d6bfe" /> <img alt="真实终端" src="https://img.shields.io/badge/-真实终端-4d6bfe" /> <img alt="Git 面板" src="https://img.shields.io/badge/-Git%20面板-4d6bfe" /> <img alt="后台任务" src="https://img.shields.io/badge/-后台任务-4d6bfe" /> <img alt="侧边对话" src="https://img.shields.io/badge/-侧边对话-4d6bfe" /> <img alt="插件接入" src="https://img.shields.io/badge/-插件接入-4d6bfe" /><br /><br />
+  <img alt="文件管理" src="https://img.shields.io/badge/-文件管理-4d6bfe" /> <img alt="编辑预览" src="https://img.shields.io/badge/-编辑预览-4d6bfe" /> <img alt="内嵌浏览器" src="https://img.shields.io/badge/-内嵌浏览器-4d6bfe" /> <img alt="真实终端" src="https://img.shields.io/badge/-真实终端-4d6bfe" /> <img alt="文件变动" src="https://img.shields.io/badge/-文件变动-4d6bfe" /> <img alt="后台任务" src="https://img.shields.io/badge/-后台任务-4d6bfe" /> <img alt="侧边对话" src="https://img.shields.io/badge/-侧边对话-4d6bfe" /> <img alt="插件接入" src="https://img.shields.io/badge/-插件接入-4d6bfe" /><br /><br />
   <b>右侧栏 + 底部面板双工作台</b>，并把 <code>ctx.betterSidebar</code> 服务开放给所有插件——<br />
   通过 <code>registerTab</code> / <code>registerFileViewer</code> 注册新的侧边栏页面与文件预览器。
 </div>
@@ -44,7 +44,7 @@
 - **🌐 内嵌浏览器**：多开网页 tab，后退 / 前进 / 刷新；内容运行在沙箱 iframe；外链默认按协议分流——HTTP 在侧边栏打开、HTTPS 走系统浏览器（设置页可分别调整）
 - **💻 真实终端**：xterm.js + node-pty 真实 shell，断线重连回放；可选为模型注入 `terminal_*` 工具
 - **📂 模型侧边栏打开（可选）**：全局设置开启后注入 `sidebar_open` 工具——模型可主动在侧边栏打开文件 / 文件夹（树以该目录为根）/ HTTP(S) 网页
-- **🌿 Git 面板**：真 diff + VSCode 式 diff tab、历史、右键暂存 / 提交 / 还原；工作区容器下自动发现子仓库并显示**仓库选择器**，支持 linked worktree 变更发现
+- **🌿 文件变动**：Git 视角（真 diff / 历史 / 暂存·提交·还原 / worktree·子仓库选择）与本轮文件视角（模型读 / 写 / 编辑实时追踪，按文件分组、按类型筛选）**双视角合一**；统一 diff 渲染（改蓝配对 + 行内字符级高亮 + 语法着色 + 上下文折叠），底部可拖拽预览面板，可一键展开为独立 diff tab
 - **🧩 后台任务页**：subagent 拓扑 + 后台任务（退出码 / 实时输出 / 强制终止）
 - **💬 侧边对话(beta)**：Codex 风格的侧边线程——继承主会话完整上下文（含进行中的回合与工具调用）独立运行，不进入主会话；线程内可持续追问，一键「保存为新会话」提升为顶层会话
 - **🪟 双工作台**：右侧栏 + 底部面板；拖 Tab 拆分 / 合并分栏（可跨面板），移动端自动合并全宽抽屉
@@ -162,10 +162,9 @@ dsh registry enable dsh-external/dsh-better-sidebar
 |---|---|
 | **🗂️ 文件工作台：资源管理器**<br/><sub>支持两种格式的资源管理器：内嵌在文件预览中 / 独立显示文件树。懒加载目录树、软链接按目标类型展示（目录软链接可展开、失效链接标红）、全局文件名搜索、上传文件/文件夹与拖放上传、右键菜单（在新 Tab 打开 / 在侧边打开 / 复制路径）、悬浮 `@文件` 一键引用进输入框。</sub><br/><div align="center"><img width="420" alt="文件资源管理器" src="https://github.com/user-attachments/assets/a410bfd2-a8ba-43e6-873e-22417756e94d" /></div> | **📝 Markdown · 图片 · PDF 内联预览**<br/><sub>Markdown 预览支持 **Mermaid 图表**（`securityLevel: 'strict'` 安全渲染 + 二次清洗；点击图表弹窗放大、滚轮缩放、拖拽平移）、**README 级内嵌 HTML**（徽章墙 `<div align=center>`、`<details>` 折叠块内嵌 markdown、表格单元格内联标签——DOMPurify 白名单消毒真实渲染，`<script>` 等活性内容剥除，本地图片经会话媒体路由重写）与**浮动目录大纲**（≥3 标题出现，点击平滑跳转、自动展开折叠块）；图片 / PDF 走媒体路由内联展示；Office 三件套由生态插件补齐。</sub><br/><div align="center"><img width="420" alt="Markdown + Mermaid 预览" src="https://github.com/user-attachments/assets/fe0e5182-55bb-45cc-b98b-a2877c2bdd38" /></div> |
 | **🖥️ CodeMirror 代码编辑器**<br/><div align="center"><img width="420" alt="CodeMirror 代码编辑器" src="https://github.com/user-attachments/assets/b44b488e-568c-4ee0-b96c-e9c906598a77" /></div> | **🖼️ 图片内联预览**<br/><div align="center"><img width="420" alt="图片内联预览" src="https://github.com/user-attachments/assets/f9a58c30-5b7a-48b5-9e22-37d7e071f593" /></div> |
-| **💻 真实终端**<br/><sub>xterm.js + node-pty 真实 shell（不是模拟器）：断线重连 transcript 回放、shell / shellArgs 可配置（设置页或 `cordis.patch.yml`）、可选为模型注入 `terminal_*` 工具（agent 可直接开终端跑命令）。</sub><br/><div align="center"><img width="420" alt="真实终端" src="https://github.com/user-attachments/assets/0dad6ad3-ff3f-4b5a-86d2-f832ce65323e" /></div> | **🌿 Git 面板**<br/><sub>暂存 / 取消暂存 / 提交（`Ctrl+Enter`）/ 还原，历史列表；点击改动文件打开 **VSCode 式 diff tab**（红绿行级对比）。</sub><br/><div align="center"><img width="420" alt="Git 面板" src="https://github.com/user-attachments/assets/e7fc1220-305f-4bca-8583-e77ab4f4fa78" /></div> |
+| **💻 真实终端**<br/><sub>xterm.js + node-pty 真实 shell（不是模拟器）：断线重连 transcript 回放、shell / shellArgs 可配置（设置页或 `cordis.patch.yml`）、可选为模型注入 `terminal_*` 工具（agent 可直接开终端跑命令）。</sub><br/><div align="center"><img width="420" alt="真实终端" src="https://github.com/user-attachments/assets/0dad6ad3-ff3f-4b5a-86d2-f832ce65323e" /></div> | **🌿 文件变动：Git 视角 + 本轮文件**<br/><sub>双视角合一：**Git 视角**保留完整源代码管理（暂存 / 取消暂存 / 提交（`Ctrl+Enter`）/ 还原、历史、worktree 与子仓库选择）；**本轮文件视角**实时折叠会话事件日志，记录模型读 / 写 / 编辑的每个文件（按文件分组、按类型筛选、操作数角标）。点击任意改动在底部**可拖拽预览面板**查看统一 diff——删红 / 增绿 / 改蓝配对 + 行内字符级高亮 + 语法着色 + 上下文折叠——也可一键展开为 VSCode 式独立 diff tab（同一渲染栈）。</sub><br/><div align="center"><img width="420" alt="文件变动" src="https://github.com/user-attachments/assets/e7fc1220-305f-4bca-8583-e77ab4f4fa78" /></div> |
 | **🌐 内嵌浏览器**<br/><sub>多开网页 tab：后退 / 前进 / 刷新 / 地址栏；内容运行在**不透明源沙箱 iframe**（界面实时显示沙箱状态，可按页面临时解锁）；聊天里的外链点击可被接管到侧边栏打开（按协议分流，可配）。</sub><br/><div align="center"><img width="420" alt="内嵌浏览器" src="https://github.com/user-attachments/assets/9bc6b65a-64fc-4942-a685-76e391e55606" /></div> | **🧩 任务页：子代理拓扑 + 后台任务**<br/><sub>子代理树实时拓扑（运行状态、批量实时预览）+ 后台任务清单（退出码 / 实时输出 / 强制终止）；新子代理 / 新任务可自动展开侧边栏（可关）。</sub><br/><div align="center"><img width="420" alt="任务页：子代理拓扑" src="https://github.com/user-attachments/assets/dcd8ed2f-59fa-405b-937b-2d250f5034dd" /></div> |
 | **💬 侧边对话(beta)**<br/><sub>Codex 风格侧边线程：**每个对话一个独立 Tab**；线程继承主会话完整上下文（含进行中回合，以 interrupted 诚实冻结）独立运行，不污染主会话；可持续追问、重启冷恢复；一键「保存为新会话」提升为顶层会话。</sub><br/><div align="center"><img width="420" alt="侧边对话(beta)" src="https://github.com/user-attachments/assets/3a338c36-f5de-4000-95f3-4b1cd04f60fc" /></div> | **🪟 双工作台：右侧栏 + 底部面板 + 分栏**<br/><sub>右侧栏与底部面板可同时展开；拖 Tab 到分栏边缘**拆分**、拖到中间**合并**（可跨面板）；面板宽高左缘/上缘拖拽调节；移动端自动合并为全宽抽屉；把 tab 拖到主会话区域可变为**自由窗口**（悬浮 / 缩放 / 置顶，拖回 pane 停靠）。</sub><br/><div align="center"><img width="420" alt="双工作台（右侧栏 + 底部面板）" src="https://github.com/user-attachments/assets/dfdb875e-a1a8-4d4b-8340-353736b1708f" /></div> |
-| **📜 文件追踪**<br/><sub>记录模型在本会话读 / 写 / 编辑过的每一个文件（读取会话事件日志实时折叠），按文件分组、带操作数角标；点开任意操作查看**行级 diff**（删红 / 增绿 / 改蓝 + 行内字符级高亮）或带真实行号的读取视图，常见语言**语法着色**（关键字 / 字符串 / 数字 / 类型 / 函数 / 注释 / 预处理，跨行块注释正确），失败操作直接展示真实错误文本，长行与未变更区间可折叠。移植自独立插件 [dsh-file-trace](https://github.com/lhh010/dsh-file-trace)（仍独立维护，二者可共存；本内置 tab 可在设置页整体关闭）。</sub> |
 | **⚙️ 声明式设置**<br/><sub>设置页「侧边卡片」分区：每个 tab / 预览器一张小卡片，独立开关（高亮启用态 + 品牌开关滑块）；二级设置经卡片底部「功能设置」条弹窗（开关 / 文本 / 数字 / 下拉）；插件自有设置持久化在 `pluginSettings`。</sub><br/><div align="center"><img width="420" alt="声明式设置：侧边卡片" src="https://github.com/user-attachments/assets/0800ca64-621e-48da-b7df-aecfddc3ec29" /></div> | **📱 移动端**<br/><sub>窄屏（<768px）自动切换为全宽抽屉：底栏 tab 一次性并入右侧栏，触屏拖拽可调。</sub><br/><div align="center"><img width="360" alt="移动端全宽抽屉" src="https://github.com/user-attachments/assets/a82ba78a-f4cf-4d85-80e8-050a05beb144" /></div> |
 
 ## 🌐 插件生态
diff --git a/README_EN.md b/README_EN.md
index f2a4db2..9c29a00 100644
--- a/README_EN.md
+++ b/README_EN.md
@@ -11,7 +11,7 @@
   <a href="https://dshfind.com/en/plugins/omdsh-dev/DSH-better-sidebar?ref=badge"><img alt="dshfind" src="https://dshfind.com/api/badge/omdsh-dev/DSH-better-sidebar?lang=en" /></a><br /><br />
   <a href="https://www.npmjs.com/package/@deepseek-ai/dsh?activeTab=versions"><img alt="Supported DSH versions (v0.18.0-alpha.0 alpha track): 0.1.2-alpha.2" src="https://img.shields.io/badge/DSH-0.1.2--alpha.2_(alpha%20track)-4d6bfe" /></a>
   <a href="https://github.com/topics/dsh-better-sidebar"><img alt="Plugin ecosystem: GitHub topic dsh-better-sidebar" src="https://img.shields.io/badge/plugin%20ecosystem-topic%20dsh--better--sidebar-4d6bfe" /></a><br /><br />
-  <img alt="File management" src="https://img.shields.io/badge/-File%20management-4d6bfe" /> <img alt="Edit &amp; preview" src="https://img.shields.io/badge/-Edit%20%26%20preview-4d6bfe" /> <img alt="Embedded browser" src="https://img.shields.io/badge/-Embedded%20browser-4d6bfe" /> <img alt="Real terminal" src="https://img.shields.io/badge/-Real%20terminal-4d6bfe" /> <img alt="Git panel" src="https://img.shields.io/badge/-Git%20panel-4d6bfe" /> <img alt="Background tasks" src="https://img.shields.io/badge/-Background%20tasks-4d6bfe" /> <img alt="Side Chat" src="https://img.shields.io/badge/-Side%20Chat-4d6bfe" /> <img alt="Plugin integration" src="https://img.shields.io/badge/-Plugin%20integration-4d6bfe" /><br /><br />
+  <img alt="File management" src="https://img.shields.io/badge/-File%20management-4d6bfe" /> <img alt="Edit &amp; preview" src="https://img.shields.io/badge/-Edit%20%26%20preview-4d6bfe" /> <img alt="Embedded browser" src="https://img.shields.io/badge/-Embedded%20browser-4d6bfe" /> <img alt="Real terminal" src="https://img.shields.io/badge/-Real%20terminal-4d6bfe" /> <img alt="Changes" src="https://img.shields.io/badge/-Changes-4d6bfe" /> <img alt="Background tasks" src="https://img.shields.io/badge/-Background%20tasks-4d6bfe" /> <img alt="Side Chat" src="https://img.shields.io/badge/-Side%20Chat-4d6bfe" /> <img alt="Plugin integration" src="https://img.shields.io/badge/-Plugin%20integration-4d6bfe" /><br /><br />
   <b>A dual workbench (right sidebar + bottom panel)</b> that opens its <code>ctx.betterSidebar</code> service to every plugin —<br />
   register new sidebar pages and file viewers via <code>registerTab</code> / <code>registerFileViewer</code>.
 </div>
@@ -44,7 +44,7 @@
 - **🌐 Embedded Browser**: multiple web tabs with back / forward / refresh; content runs in a sandboxed iframe; external links are routed by protocol by default — HTTP opens in the sidebar, HTTPS goes to the system browser (both adjustable in settings)
 - **💻 Real Terminal**: xterm.js + node-pty real shell, reconnect with transcript replay; optionally injects `terminal_*` tools for the model
 - **📂 Model-driven sidebar opens (opt-in)**: with the global setting on, the `sidebar_open` tool lets the model actively open files / folders (tree rooted there) / HTTP(S) pages in the sidebar
-- **🌿 Git Panel**: real diff + VSCode-style diff tabs, history, right-click to stage / commit / revert; under a workspace container it discovers child repositories and shows a **repository selector**, with linked-worktree change discovery
+- **🌿 Changes**: one tab, two lenses — **Git** (real diff / history / stage·commit·revert / worktree & child-repo selection) and **This Session** (live tracking of every file the model reads / writes / edits, grouped by file with kind filters); a unified diff renderer (mod pairing + intra-line character highlights + syntax coloring + context folding), a draggable bottom preview pane, and one-click expansion into a dedicated diff tab
 - **🧩 Background Tasks**: agent topology + background tasks (exit codes / live output / force-kill)
 - **💬 Side Chat (beta)**: Codex-style side threads — the child inherits the parent's FULL context (completed turns + the pending question + the in-progress turn's assistant output and tool activity, honestly frozen as "interrupted") and runs independently without entering the main conversation; threads support continuous follow-ups (auto-resumed after a DSH restart) and one-click "Save as new session" promotion to a top-level session
 - **🪟 Dual Workbench**: right sidebar + bottom panel; drag tabs to split / merge panes (cross-panel), mobile auto-merges into a full-width drawer
@@ -162,10 +162,9 @@ Update: `git pull && pnpm install && pnpm build` → `node scripts/package-regis
 |---|---|
 | **🗂️ File Workbench: Explorer**<br/><sub>Two explorer modes: embedded in the file preview / standalone file tree. Lazy-loading directory tree, symlinks classified by target kind (directory links expand, dangling links flagged), global filename search, file/folder upload buttons plus drag-drop upload, context menu (open in new tab / open to the side / copy paths), and a hover `@file` button that references a file straight into the composer.</sub><br/><div align="center"><img width="420" alt="File explorer" src="https://github.com/user-attachments/assets/a410bfd2-a8ba-43e6-873e-22417756e94d" /></div> | **📝 Inline Preview: Markdown · Images · PDF**<br/><sub>The Markdown preview renders **Mermaid diagrams** (strict-mode safe rendering + a second sanitize pass; click a diagram for a zoom modal with wheel-zoom and drag-pan), **README-level inline HTML** (badge walls `<div align=center>`, `<details>` blocks nesting markdown, inline tags in table cells — DOMPurify-sanitized, `<script>` stripped, local media rewritten to the session media route) and a floating **table of contents** (appears with ≥3 headings, smooth-scroll jumping, auto-expanding folded blocks); images / PDFs display inline via the media route; the Office suite is covered by an ecosystem plugin.</sub><br/><div align="center"><img width="420" alt="Markdown + Mermaid preview" src="https://github.com/user-attachments/assets/fe0e5182-55bb-45cc-b98b-a2877c2bdd38" /></div> |
 | **🖥️ CodeMirror editor**<br/><div align="center"><img width="420" alt="CodeMirror editor" src="https://github.com/user-attachments/assets/b44b488e-568c-4ee0-b96c-e9c906598a77" /></div> | **🖼️ Inline image preview**<br/><div align="center"><img width="420" alt="Inline image preview" src="https://github.com/user-attachments/assets/f9a58c30-5b7a-48b5-9e22-37d7e071f593" /></div> |
-| **💻 Real Terminal**<br/><sub>xterm.js + node-pty real shell (not an emulator): transcript replay on reconnect, configurable shell / shellArgs (settings page or `cordis.patch.yml`), and optional `terminal_*` model tools so the agent can open terminals and run commands itself.</sub><br/><div align="center"><img width="420" alt="Real terminal" src="https://github.com/user-attachments/assets/0dad6ad3-ff3f-4b5a-86d2-f832ce65323e" /></div> | **🌿 Git Panel**<br/><sub>Stage / unstage / commit (`Ctrl+Enter`) / revert, plus a history list; clicking a changed file opens a **VSCode-style diff tab** (line-level red/green).</sub><br/><div align="center"><img width="420" alt="Git panel" src="https://github.com/user-attachments/assets/e7fc1220-305f-4bca-8583-e77ab4f4fa78" /></div> |
+| **💻 Real Terminal**<br/><sub>xterm.js + node-pty real shell (not an emulator): transcript replay on reconnect, configurable shell / shellArgs (settings page or `cordis.patch.yml`), and optional `terminal_*` model tools so the agent can open terminals and run commands itself.</sub><br/><div align="center"><img width="420" alt="Real terminal" src="https://github.com/user-attachments/assets/0dad6ad3-ff3f-4b5a-86d2-f832ce65323e" /></div> | **🌿 Changes: Git lens + This-Session lens**<br/><sub>Two lenses on "what changed?": the **Git lens** keeps the full source-control surface (stage / unstage / commit (`Ctrl+Enter`) / revert, history, worktree and child-repo selectors); the **This Session** lens folds the session event log live, recording every file the model read / wrote / edited (grouped by file, kind-filtered, op-count badge). Clicking any change previews it in the **draggable bottom pane** with the unified diff — del red / add green / mod-blue pairing + intra-line character highlights + syntax coloring + context folding — or expands into a VSCode-style dedicated diff tab (same rendering stack).</sub><br/><div align="center"><img width="420" alt="Changes" src="https://github.com/user-attachments/assets/e7fc1220-305f-4bca-8583-e77ab4f4fa78" /></div> |
 | **🌐 Embedded Browser**<br/><sub>Multiple web tabs with back / forward / reload / address bar; content runs in an **opaque-origin sandboxed iframe** (live sandbox status in the UI, per-page temporary unlock available); external-link clicks in the chat can be taken over into the sidebar (protocol-based routing, configurable).</sub><br/><div align="center"><img width="420" alt="Embedded browser" src="https://github.com/user-attachments/assets/9bc6b65a-64fc-4942-a685-76e391e55606" /></div> | **🧩 Tasks: Agent Topology + Background Jobs**<br/><sub>Live subagent-tree topology (run states, batched live previews) plus the background-jobs list (exit codes / live output / force-kill); new subagents / jobs can auto-expand the sidebar (configurable).</sub><br/><div align="center"><img width="420" alt="Tasks: subagent topology" src="https://github.com/user-attachments/assets/dcd8ed2f-59fa-405b-937b-2d250f5034dd" /></div> |
 | **💬 Side Chat (beta)**<br/><sub>Codex-style side threads: **one independent tab per conversation**; the thread inherits the parent's full context (including the in-progress turn, honestly frozen as "interrupted") and runs independently without polluting the main session; follow-ups survive restarts; one click promotes the thread to a top-level session.</sub><br/><div align="center"><img width="420" alt="Side Chat (beta)" src="https://github.com/user-attachments/assets/3a338c36-f5de-4000-95f3-4b1cd04f60fc" /></div> | **🪟 Dual Workbench: Sidebar + Bottom Panel + Split Panes**<br/><sub>The right sidebar and the bottom panel can stay open together; drag a tab to a pane edge to **split**, to the middle to **merge** (works across panels); panel width/height drag from the left/top edge; on mobile everything merges into a full-width drawer; drag a tab onto the main conversation area to turn it into a **free window** (float / resize / raise, drag back onto a pane to dock).</sub><br/><div align="center"><img width="420" alt="Dual workbench (right sidebar + bottom panel)" src="https://github.com/user-attachments/assets/dfdb875e-a1a8-4d4b-8340-353736b1708f" /></div> |
-| **📜 File Trace**<br/><sub>Records every file the model read, wrote, or edited in this session (folded live from the session event log), grouped by file with an op-count badge; open any op for a **line diff** (del red / add green / mod blue + intra-line character highlighting) or the line-numbered read view, with lightweight **syntax coloring** for common languages (keywords / strings / numbers / types / functions / comments / preprocessor, multi-line block comments included); failed ops show their real error text, and long lines and unchanged regions fold. Ported from the standalone [dsh-file-trace](https://github.com/lhh010/dsh-file-trace) plugin (still maintained independently; both can coexist — this built-in tab can be turned off in settings).</sub> |
 | **⚙️ Declarative Settings**<br/><sub>The "Side card" section in DSH settings: one small card per tab / viewer with an independent toggle (highlighted enabled state + brand switch); secondary settings open from the "Feature settings" strip at the card bottom (switch / text / number / select rows); plugin-owned settings persist under `pluginSettings`.</sub><br/><div align="center"><img width="420" alt="Declarative settings: side cards" src="https://github.com/user-attachments/assets/0800ca64-621e-48da-b7df-aecfddc3ec29" /></div> | **📱 Mobile**<br/><sub>On narrow screens (<768px) the panels become a full-width drawer: bottom-panel tabs merge into the sidebar once, with touch-friendly dragging.</sub><br/><div align="center"><img width="360" alt="Mobile full-width drawer" src="https://github.com/user-attachments/assets/a82ba78a-f4cf-4d85-80e8-050a05beb144" /></div> |
 
 ## 🌐 Plugin Ecosystem
diff --git a/docs/external-plugin-guide.md b/docs/external-plugin-guide.md
index 38879c3..4ed639f 100644
--- a/docs/external-plugin-guide.md
+++ b/docs/external-plugin-guide.md
@@ -15,7 +15,7 @@ better-sidebar 从 v0.4.0 起把自己改造成一个**注册表服务**：
 - **新页面（tab）**：注册一种新的侧边栏 tab 类型，出现在侧边栏 `+` 菜单里，用户点击后在自己的分栏里打开你的 React 页面；
 - **文件预览器（file viewer）**：注册一种文件类型预览器，让用户在侧边栏打开文件时走你的渲染组件（覆盖或补充内置的 image/pdf/code 等）。
 
-内置的 8 个 tab（editor / git / subagent / sidechat / terminal / browser / file-trace / diff）和 6 个 viewer（image / pdf / markdown / html / code / binary-download）**自己也是通过同一套 API 注册的**（吃自己的狗粮），所以外部插件的能力与内置功能完全对等。
+内置的 7 个 tab（editor / git——「文件变动」统一 tab（Git 视角 + 本轮文件视角）/ subagent / sidechat / terminal / browser / diff）和 6 个 viewer（image / pdf / markdown / html / code / binary-download）**自己也是通过同一套 API 注册的**（吃自己的狗粮），所以外部插件的能力与内置功能完全对等。
 
 关键机制一句话：better-sidebar 的 client half 在 `apply()` 开头执行 `ctx.provide('betterSidebar', service)`（`src/client/index.tsx`），消费插件在 `inject` 里声明 `'betterSidebar'`，Cordis 保证服务就绪后才激活你的插件，然后你调用 `ctx.betterSidebar.registerTab(...)` / `registerFileViewer(...)` 完成注册，返回的 disposer 由 Cordis fiber 在卸载（HMR / 禁用）时自动调用。
 
@@ -157,7 +157,7 @@ interface TabDescriptor {
   title: string | (() => string)
   /** 图标：ReactNode 或 (size: number) => ReactNode */
   icon?: ReactNode | ((size: number) => ReactNode)
-  /** + 菜单排序（升序）；默认 100。内置：editor=10, git=20, subagent=30, sidechat=35, terminal=40, browser=50, file-trace=55=50 */
+  /** + 菜单排序（升序）；默认 100。内置：editor=10, git=20, subagent=30, sidechat=35, terminal=40, browser=50 */
   order?: number
   /** 从 + 菜单隐藏（editor/diff 用：由其他流程触发打开，不在菜单里） */
   hidden?: boolean
@@ -359,12 +359,12 @@ ctx.effect(() => {
 | id | order | single | hidden | 用途 |
 |---|---|---|---|---|
 | `editor` | 10 | 否（按 path 去重） | 否 | 唯一「文件窗口」（编辑/预览 + 资源管理）。chrome 恒合并形态：路径输入框 + 编辑器控件 + 可开关内嵌文件树（全局搜索 `fs.search`；状态存 `tab.meta.treeOpen/treeWidth`）。`editorExplorer`：关（默认）= 按 path 新开，无路径窗口 = 纯资源管理器；开 = 树点击/Enter 经 `updateTab` 原地切换（id/meta 不变），无路径窗口 = 带 chrome 空窗口。树右键「在新 Tab 中打开」「在侧边打开」（pane 右侧 split）。新会话 seed 空文件窗口（`title:'Files'`）；旧 `explorer` tab 经 `sanitizeState` 迁移 |
-| `git` | 20 | 是 | 否 | Git 面板 |
+| `git` | 20 | 是 | 否 | 「文件变动」统一 tab（id 保留 `git` 以兼容持久化布局）：**Git 视角**（原 Git 面板：staged/unstaged / 提交 / 历史 / worktree·子仓库选择）+ **本轮文件视角**（原 file-trace：会话事件日志实时折叠的模型读写编辑记录，按文件分组、类型筛选、badge 计数）；两视角共用底部可拖拽预览面板（`tab.meta.lens/previewH` 持久化），diff 渲染统一走 `src/client/diff/`（`DiffRows`/`DiffFiles`：mod 配对 + 行内高亮 + 语法着色 + 上下文折叠） |
 | `subagent` | 30 | 是 | 否 | 子代理拓扑 |
 | `sidechat` | 35 | 否（`sidechat:<uuid>`，按 `meta.threadId` 去重） | 否 | 侧边对话（每对话一 Tab）：打开即建空线程（首条消息赢得标签并同步标题）；线程 = 插件自建子会话（种子继承父会话上下文，进行中回合以 `interrupted` 闭合；种子带合法 `subagent/descriptor`，SubagentView 按 `Side: ` 前缀过滤），`origin:'subagent'` 隐藏于主列表；走 `/sidebar/api/sidechat.*` 路由；头部菜单切换/重开（`parkSidechatReopen` + 确定性 id），关 Tab 释放 live agent；重开经 `collectOwnEvents` 回源到种子边界；「保存为新会话」= `session.fork`（`this` 敏感）。[设计文档](plans/2026-08-20-sidechat-tab-design.md) |
 | `terminal` | 40 | 否（`terminal:<n>`） | 否 | 终端。v0.17.0+ 右键「固定到工作区/全局」：跨会话不消失，TabBar 内联虚拟 Tab（`pinned:<homeSessionId>:<tabId>`），就地按 home scope 连 PTY；global 全会话可见、workspace 仅同 cwd；`tab.pin = { scope, homeCwd? }` 随会话持久化，渲染期解析（`collectPinnedTabs` → `createPinnedVirtualTab` → `injectPinnedIntoTree`） |
 | `browser` | 50 | 否（`browser:<n>`） | 否 | 内嵌浏览器（沙箱 iframe，可设置关沙箱） |
-| `diff` | -1 | 否（按 id 去重） | 是 | 差异查看（GitView 触发） |
+| `diff` | -1 | 否（按 id 去重） | 是 | 差异查看（changes tab 的预览面板「展开为独立页签」触发，同一渲染栈） |
 
 你的 `id` 不可与上述重复，否则 `registerTab` 抛 `"tab type \"X\" already registered"`。
 
diff --git a/src/client/DiffTab.tsx b/src/client/DiffTab.tsx
index 8aaef04..2720abc 100644
--- a/src/client/DiffTab.tsx
+++ b/src/client/DiffTab.tsx
@@ -1,18 +1,19 @@
 /**
- * The diff tab: one change opened from the git panel, like VSCode's diff
+ * The diff tab: one change opened from the changes tab, like VSCode's diff
  * editor. A worktree ref loads the file's unified diff (`git diff`, staged or
  * not; untracked files — which git diff never covers — render as a full-file
  * addition from their content), a commit ref loads the commit's full patch
  * (`git.show`-style). The header carries a refresh button because the tab
- * stays mounted while the git panel's staging/discard operations change the
- * very content it shows.
+ * stays mounted while the changes tab's staging/discard operations change the
+ * very content it shows. Rendering goes through the shared {@link DiffFiles}
+ * renderer — the same one the changes tab's inline preview uses.
  */
 import { useCallback, useEffect, useState } from 'react'
 import { IconRefreshOutline16 } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { SessionScope } from './api.ts'
 import { api } from './api.ts'
 import type { SidebarDiffRef } from './state.ts'
-import { DiffView } from './DiffView.tsx'
+import { DiffFiles } from './diff/DiffFiles.tsx'
 import { t } from './locales.ts'
 import { resolveSidebarPath } from './produced-files.ts'
 import css from './sidebar.module.css'
@@ -102,8 +103,8 @@ export function DiffTab(props: { sessionId: string; cwd: string | undefined; dif
       {!loading && error === null && data !== null && (
         <>
           {data.untracked !== undefined
-            ? <DiffView diff="" untrackedPath={diff.kind === 'worktree' ? diff.path : ''} untrackedContent={data.untracked} />
-            : <DiffView diff={data.diff} />}
+            ? <DiffFiles diff="" untrackedPath={diff.kind === 'worktree' ? diff.path : ''} untrackedContent={data.untracked} />
+            : <DiffFiles diff={data.diff} />}
           {data.diff === '' && data.untracked === undefined && (
             <div className={css.gitEmpty}>{t('diffEmpty')}</div>
           )}
diff --git a/src/client/DiffView.tsx b/src/client/DiffView.tsx
deleted file mode 100644
index e6705b7..0000000
--- a/src/client/DiffView.tsx
+++ /dev/null
@@ -1,305 +0,0 @@
-/**
- * The real diff surface for the git panel: parses the host's unified diff
- * text (`git diff` / `git show`) and renders it VSCode-style — per-file
- * sections with hunks (`@@ -a,b +c,d @@` headers), old/new line-number
- * gutters, and aligned context / deleted / added rows colored through the
- * DSH tokens. Untracked files produce no `git diff` output, so the caller
- * can pass the file content to render as a full-file addition instead.
- *
- * The parser is a pure function (`parseUnifiedDiff`) so the interesting
- * cases are unit-tested without a DOM.
- */
-import { useEffect, useMemo, useState, type ReactNode } from 'react'
-import clsx from 'clsx'
-import { t } from './locales.ts'
-import css from './sidebar.module.css'
-
-/** One rendered diff line. */
-export interface DiffLine {
-  kind: 'ctx' | 'del' | 'add' | 'meta'
-  /** The line content without its diff marker ('' for the no-newline marker). */
-  text: string
-  /** Old-side line number (null for pure additions / metadata). */
-  oldNum: number | null
-  /** New-side line number (null for pure deletions / metadata). */
-  newNum: number | null
-}
-
-/** One parsed hunk. */
-export interface DiffHunk {
-  /** The old-side start line (`-a[,b]`). */
-  oldStart: number
-  /** The new-side start line (`+c[,d]`). */
-  newStart: number
-  /** The section text after the trailing `@@` (may be empty). */
-  header: string
-  lines: DiffLine[]
-}
-
-/** One parsed file section of a unified diff. */
-export interface DiffFile {
-  /** The `---` path verbatim ('/dev/null' for a new file). */
-  oldPath: string
-  /** The `+++` path verbatim ('/dev/null' for a deleted file). */
-  newPath: string
-  /** The file changed with binary content: no hunks to draw. */
-  binary: boolean
-  hunks: DiffHunk[]
-}
-
-/** The parsed unified diff. */
-export interface ParsedDiff {
-  files: DiffFile[]
-}
-
-/** Parse the hunk header `@@ -a[,b] +c[,d] @@ section` (section may contain '@@'). */
-function parseHunkHeader(line: string): { oldStart: number; newStart: number; header: string } | null {
-  const match = /^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@(.*)$/.exec(line)
-  if (match === null) return null
-  return { oldStart: Number(match[1]), newStart: Number(match[3]), header: match[5] ?? '' }
-}
-
-/**
- * Parse `git diff --no-color` output into file sections and hunks. Rows
- * outside a file section (leading noise) and metadata rows between the
- * `diff --git`/`---`/`+++` headers and the first hunk (index lines, mode
- * changes, rename/similarity lines) are skipped; a section that never
- * reaches a hunk (a mode/rename-only change) stays hunkless so the caller
- * can still draw its path.
- */
-export function parseUnifiedDiff(text: string): ParsedDiff {
-  const files: DiffFile[] = []
-  let current: DiffFile | null = null
-  let inHunk = false
-  let hunk: DiffHunk | null = null
-  let oldNum = 0
-  let newNum = 0
-  const flushHunk = (): void => {
-    if (current !== null && hunk !== null) current.hunks.push(hunk)
-    hunk = null
-    inHunk = false
-  }
-  for (const raw of text.split('\n')) {
-    if (raw.startsWith('diff --git ')) {
-      flushHunk()
-      current = { oldPath: '', newPath: '', binary: false, hunks: [] }
-      files.push(current)
-      continue
-    }
-    if (current === null) continue
-    if (raw.startsWith('Binary files ') || raw === 'GIT binary patch') {
-      flushHunk()
-      current.binary = true
-      continue
-    }
-    if (raw.startsWith('--- ')) {
-      flushHunk()
-      current.oldPath = raw.slice(4)
-      continue
-    }
-    if (raw.startsWith('+++ ')) {
-      current.newPath = raw.slice(4)
-      continue
-    }
-    const header = parseHunkHeader(raw)
-    if (header !== null) {
-      flushHunk()
-      hunk = { oldStart: header.oldStart, newStart: header.newStart, header: header.header, lines: [] }
-      oldNum = header.oldStart
-      newNum = header.newStart
-      inHunk = true
-      continue
-    }
-    if (!inHunk || hunk === null) continue
-    const marker = raw[0]
-    if (marker === '\\') {
-      // `\ No newline at end of file`: metadata attached to the previous row.
-      hunk.lines.push({ kind: 'meta', text: raw.slice(1), oldNum: null, newNum: null })
-      continue
-    }
-    if (marker === ' ') {
-      hunk.lines.push({ kind: 'ctx', text: raw.slice(1), oldNum, newNum })
-      oldNum += 1
-      newNum += 1
-    } else if (marker === '-') {
-      hunk.lines.push({ kind: 'del', text: raw.slice(1), oldNum, newNum: null })
-      oldNum += 1
-    } else if (marker === '+') {
-      hunk.lines.push({ kind: 'add', text: raw.slice(1), oldNum: null, newNum })
-      newNum += 1
-    } else {
-      // Not a diff line (a hunk can never contain one): stop the hunk.
-      flushHunk()
-    }
-  }
-  flushHunk()
-  return { files }
-}
-
-/** Build the untracked-file shape: one file, one hunk of pure additions. */
-function untrackedFile(path: string, content: string): DiffFile {
-  const lines: DiffLine[] = []
-  const body = content.endsWith('\n') ? content.slice(0, -1) : content
-  if (body !== '') {
-    let num = 1
-    for (const line of body.split('\n')) {
-      lines.push({ kind: 'add', text: line, oldNum: null, newNum: num })
-      num += 1
-    }
-  }
-  return { oldPath: '/dev/null', newPath: `b/${path}`, binary: false, hunks: [{ oldStart: 0, newStart: 1, header: '', lines }] }
-}
-
-/** Strip the `a/` / `b/` prefix git puts on diff paths (not on /dev/null). */
-function displayPath(path: string): string {
-  if (path === '/dev/null') return path
-  if (path.startsWith('a/') || path.startsWith('b/')) return path.slice(2)
-  return path
-}
-
-/** The file header badge: added / deleted / renamed / binary ('' for a plain edit). */
-function fileTag(file: DiffFile): string | null {
-  if (file.binary) return t('diffBinary')
-  if (file.oldPath === '/dev/null') return t('diffAdded')
-  if (file.newPath === '/dev/null') return t('diffDeleted')
-  const oldPath = displayPath(file.oldPath)
-  const newPath = displayPath(file.newPath)
-  if (oldPath !== newPath) return t('diffRenamed')
-  return null
-}
-
-/** Cap the flattened rows like DiffBlock: head + tail, expand button between. */
-const MAX_DIFF_ROWS = 500
-
-const TEST_PATH = /(^|\/)(?:__tests__|tests?|specs?|fixtures?|mocks?|snapshots?)(?:\/|$)|\.(?:test|spec)\.[^/]+$/i
-const DOC_PATH = /(^|\/)(?:docs?|documentation)(?:\/|$)|(^|\/)(?:readme|changelog|contributing|license|authors|notice)(?:\.[^/]*)?$/i
-const GENERATED_PATH = /(^|\/)(?:dist|build|coverage|generated|vendor|node_modules)(?:\/|$)|(^|\/)(?:package-lock\.json|pnpm-lock\.yaml|yarn\.lock|bun\.lockb?|composer\.lock|cargo\.lock|poetry\.lock)$/i
-const SOURCE_PATH = /\.(?:js|jsx|mjs|cjs|ts|tsx|mts|cts|py|pyw|rb|php|java|kt|kts|scala|go|rs|swift|c|h|cc|cpp|cxx|hpp|hh|hxx|cs|fs|fsx|vb|dart|lua|r|ex|exs|erl|hrl|clj|cljs|cljc|groovy|sh|bash|zsh|fish|ps1|sql|vue|svelte|astro|html|htm|css|scss|sass|less)$/i
-
-/** Source files open by default; tests, docs, generated files and unknown types stay folded. */
-function defaultExpandedFiles(files: DiffFile[]): Set<number> {
-  const expanded = new Set<number>()
-  files.forEach((file, index) => {
-    const path = displayPath(file.newPath === '/dev/null' ? file.oldPath : file.newPath)
-    if (!file.binary && file.hunks.length > 0
-      && !TEST_PATH.test(path) && !DOC_PATH.test(path) && !GENERATED_PATH.test(path)
-      && SOURCE_PATH.test(path)) {
-      expanded.add(index)
-    }
-  })
-  return expanded
-}
-
-export interface DiffViewProps {
-  /** Unified diff text (`git.diff` or `git.commit-diff` payloads). */
-  diff: string
-  /** Untracked-file content: when present, renders as a full-file addition instead of parsing. */
-  untrackedPath?: string
-  untrackedContent?: string
-}
-
-export function DiffView({ diff, untrackedPath, untrackedContent }: DiffViewProps) {
-  const parsed = useMemo<ParsedDiff>(() => {
-    if (untrackedPath !== undefined) {
-      return { files: [untrackedFile(untrackedPath, untrackedContent ?? '')] }
-    }
-    return parseUnifiedDiff(diff)
-  }, [diff, untrackedPath, untrackedContent])
-  const [expanded, setExpanded] = useState(false)
-  const [expandedFiles, setExpandedFiles] = useState<Set<number>>(() => defaultExpandedFiles(parsed.files))
-
-  useEffect(() => { setExpandedFiles(defaultExpandedFiles(parsed.files)) }, [parsed])
-
-  // Flatten into display rows so the cap can slice a single list.
-  const rows = useMemo(() => {
-    const out: Array<{ key: string; file: DiffFile; fileIndex: number; type: 'path' | 'hunk' | 'line'; hunk?: DiffHunk; line?: DiffLine }> = []
-    parsed.files.forEach((file, fileIndex) => {
-      out.push({ key: `f${fileIndex}`, file, fileIndex, type: 'path' })
-      if (file.binary || !expandedFiles.has(fileIndex)) return
-      file.hunks.forEach((hunk, hunkIndex) => {
-        out.push({ key: `f${fileIndex}h${hunkIndex}`, file, fileIndex, type: 'hunk', hunk })
-        hunk.lines.forEach((line, lineIndex) => {
-          out.push({ key: `f${fileIndex}h${hunkIndex}l${lineIndex}`, file, fileIndex, type: 'line', hunk, line })
-        })
-      })
-    })
-    return out
-  }, [parsed, expandedFiles])
-
-  const hidden = rows.length - MAX_DIFF_ROWS
-  const capped = hidden > 0 && !expanded
-  const headLines = Math.ceil(MAX_DIFF_ROWS / 2)
-  const tailLines = MAX_DIFF_ROWS - headLines
-  const head = capped ? rows.slice(0, headLines) : rows
-  const tail = capped ? rows.slice(rows.length - tailLines) : []
-
-  if (rows.length === 0) return null
-
-  const renderRow = (row: (typeof rows)[number]): ReactNode => {
-    if (row.type === 'path') {
-      const tag = fileTag(row.file)
-      const from = displayPath(row.file.oldPath)
-      const to = displayPath(row.file.newPath)
-      const expandable = !row.file.binary && row.file.hunks.length > 0
-      const fileExpanded = expandedFiles.has(row.fileIndex)
-      return (
-        <button
-          key={row.key}
-          type="button"
-          className={css.gitDiffFile}
-          disabled={!expandable}
-          aria-expanded={expandable ? fileExpanded : undefined}
-          onClick={() => {
-            setExpandedFiles(current => {
-              const next = new Set(current)
-              if (next.has(row.fileIndex)) next.delete(row.fileIndex)
-              else next.add(row.fileIndex)
-              return next
-            })
-          }}
-        >
-          {expandable && <span aria-hidden="true" className={clsx(css.gitDiffFileChevron, fileExpanded && css.gitDiffFileChevronExpanded)}>›</span>}
-          <span className={css.gitDiffFilePath}>{to}</span>
-          {from !== to && <span className={css.gitDiffFileOld}>← {from}</span>}
-          {tag !== null && <span className={css.gitDiffFileTag}>{tag}</span>}
-        </button>
-      )
-    }
-    if (row.type === 'hunk') {
-      const hunk = row.hunk!
-      return (
-        <div key={row.key} className={css.gitDiffHunk}>
-          <span className={css.gitDiffHunkHeader}>@@ -{hunk.oldStart},{hunk.lines.filter(l => l.oldNum !== null).length} +{hunk.newStart},{hunk.lines.filter(l => l.newNum !== null).length} @@</span>
-          {hunk.header !== '' && <span className={css.gitDiffHunkSection}>{hunk.header}</span>}
-        </div>
-      )
-    }
-    const line = row.line!
-    const lineClass = line.kind === 'del' ? css.gitDiffDel : line.kind === 'add' ? css.gitDiffAdd : line.kind === 'meta' ? css.gitDiffMeta : css.gitDiffCtx
-    return (
-      <div key={row.key} className={clsx(css.gitDiffLine, lineClass)}>
-        {line.kind === 'meta'
-          ? <span className={css.gitDiffMetaText}>{line.text}</span>
-          : (
-            <>
-              <span className={css.gitDiffNum}>{line.oldNum ?? ''}</span>
-              <span className={css.gitDiffNum}>{line.newNum ?? ''}</span>
-              <span className={css.gitDiffCode}>{line.text}</span>
-            </>
-          )}
-      </div>
-    )
-  }
-
-  return (
-    <div className={css.gitDiff}>
-      {head.map(renderRow)}
-      {hidden > 0 && (
-        <button type="button" className={css.gitDiffExpand} aria-expanded={expanded} onClick={() => { setExpanded(value => !value) }}>
-          {expanded ? t('diffCollapse') : t('diffExpand', { count: hidden })}
-        </button>
-      )}
-      {tail.map(renderRow)}
-    </div>
-  )
-}
diff --git a/src/client/FenceErrorNotice.tsx b/src/client/FenceErrorNotice.tsx
index bd59c68..4049288 100644
--- a/src/client/FenceErrorNotice.tsx
+++ b/src/client/FenceErrorNotice.tsx
@@ -3,7 +3,7 @@
  * outside workspace`) is never shown as-is: the editor / file-tree error
  * slots render the localized reason plus a one-click global off — the click
  * flips the `workspaceFence` pref through the settings route, adopts the
- * returned document into the store (so every prefs reader — GitView's open
+ * returned document into the store (so every prefs reader — the changes tab's open
  * guard, the settings page — flips with it), and calls `onDisabled` so the
  * caller retries the failed operation immediately.
  */
diff --git a/src/client/TabBar.tsx b/src/client/TabBar.tsx
index 567bd47..586031b 100644
--- a/src/client/TabBar.tsx
+++ b/src/client/TabBar.tsx
@@ -88,7 +88,7 @@ export function TabBar(props: {
   } = props
   const [menuOpen, setMenuOpen] = useState(false)
   // The tab right-click context menu: the target tab plus the cursor
-  // position (the portaled Menu anchors there, following GitView/FileTree).
+  // position (the portaled Menu anchors there, following the git lens/FileTree).
   const [tabMenu, setTabMenu] = useState<{ tabId: string; x: number; y: number } | null>(null)
   const [dragOver, setDragOver] = useState(false)
   const listRef = useRef<HTMLDivElement>(null)
diff --git a/src/client/builtins/tabs.tsx b/src/client/builtins/tabs.tsx
index 49632c7..e8d514d 100644
--- a/src/client/builtins/tabs.tsx
+++ b/src/client/builtins/tabs.tsx
@@ -1,14 +1,14 @@
 /**
- * The 8 built-in tab descriptors: the plugin registers its own pages
- * (editor / git / subagent / sidechat / terminal / browser / diff /
- * file-trace) through
+ * The 7 built-in tab descriptors: the plugin registers its own pages
+ * (editor / git — the unified changes tab / subagent / sidechat / terminal /
+ * browser / diff) through
  * the same {@link BetterSidebarService} external plugins use — eating its
  * own dogfood. The terminal descriptor owns its quota (`TERMINAL_LIMIT`)
  * and mints `terminal:<uuid>` ids through `createTab`; the browser mints
  * `browser:<n>` the same way (no quota). The editor IS the files window
  * (the old standalone explorer merged into it).
  */
-import { IconBranchOutline16, IconCodeOutline16, IconFolderOpen16, IconNewChatOutline16, IconPanelLeftOutline16, IconThinkOutline16 } from '@deepseek-ai/dsh-client-ui-primitives'
+import { IconCodeOutline16, IconFolderOpen16, IconNewChatOutline16, IconPanelLeftOutline16, IconThinkOutline16 } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { Context } from '../../context-types.ts'
 import { allLeaves, isAgentTabId, type SidebarState } from '../state.ts'
 import { t } from '../locales.ts'
@@ -16,15 +16,14 @@ import { openSidebarFile } from '../intercept.tsx'
 import { EditorHost } from '../EditorHost.tsx'
 import { OpenWithSettings } from '../open-with-settings.tsx'
 import { lazyChunkComponent } from '../lazy-chunk.tsx'
-import { GitView } from '../GitView.tsx'
+import { ChangesTab } from '../changes/ChangesTab.tsx'
+import { extractFileOps } from '../changes/ops.ts'
 import { DiffTab } from '../DiffTab.tsx'
 import { SubagentView } from '../SubagentView.tsx'
 import { consumeSidechatSeed, SideChatView, sidechatThreadIdOf } from '../SideChatView.tsx'
 import { api } from '../api.ts'
 import { BrowserView } from '../BrowserView.tsx'
-import { IconTerminalOutline16, IconDiffOutline16, IconGlobeOutline16, IconHistoryOutline16 } from '../icons.tsx'
-import { FileTraceTab } from '../filetrace/FileTraceTab.tsx'
-import { extractFileOps } from '../filetrace/ops.ts'
+import { IconTerminalOutline16, IconDiffOutline16, IconGlobeOutline16 } from '../icons.tsx'
 import { TERMINAL_FONT_SIZE_MAX, TERMINAL_FONT_SIZE_MIN } from '../../prefs-shared.ts'
 import type { ComponentType } from 'react'
 import type { SessionScope } from '../api.ts'
@@ -142,18 +141,30 @@ export function builtinTabs(ctx: Context, options: BuiltinTabOptions = {}): read
       ),
     },
     {
+      // The unified changes tab (id kept as 'git' so persisted layouts keep
+      // resolving): the Git lens is the former source-control panel; the
+      // session lens is the former file-trace tab (PR #471). Both preview
+      // through one shared diff stack, and the badge counts this session's
+      // file ops (live from the event log — the git status itself needs a
+      // fetch, so it stays out of the badge).
       id: 'git',
-      title: () => t('git'),
-      icon: (size: number) => <IconBranchOutline16 size={size} />,
+      title: () => t('changes'),
+      icon: (size: number) => <IconDiffOutline16 size={size} />,
       order: 20,
       single: true,
-      component: ({ ctx, store, scope, visible, onOpenDiff }) => (
-        <GitView
-          scope={scope}
+      badge: (ctx, scope) => {
+        const events = ctx.sessions.get(scope.sessionId)?.events
+        return events === undefined ? null : extractFileOps(events).length
+      },
+      component: ({ ctx, store, scope, tab, visible, onOpenFile, onOpenDiff }) => (
+        <ChangesTab
+          ctx={ctx}
           store={store}
+          scope={scope}
+          tab={tab}
           visible={visible}
           onOpenFile={(path) => { openSidebarFile(ctx, store, scope.sessionId, path) }}
-          onOpenDiff={onOpenDiff ?? (() => { /* no-op */ })}
+          onOpenDiff={onOpenDiff}
         />
       ),
     },
@@ -338,21 +349,9 @@ export function builtinTabs(ctx: Context, options: BuiltinTabOptions = {}): read
       }),
       component: (props) => <BrowserView {...props} />,
     },
-    {
-      id: 'file-trace',
-      title: () => t('fileTrace'),
-      icon: (size: number) => <IconHistoryOutline16 size={size} />,
-      order: 55,
-      single: true,
-      badge: (ctx, scope) => {
-        const events = ctx.sessions.get(scope.sessionId)?.events
-        return events === undefined ? null : extractFileOps(events).length
-      },
-      component: (props) => <FileTraceTab {...props} />,
-    },
     {
       id: 'diff',
-      title: () => t('git'),
+      title: () => t('changes'),
       icon: (size: number) => <IconDiffOutline16 size={size} />,
       order: -1,
       hidden: true,
diff --git a/src/client/changes/ChangesTab.tsx b/src/client/changes/ChangesTab.tsx
new file mode 100644
index 0000000..8053ccb
--- /dev/null
+++ b/src/client/changes/ChangesTab.tsx
@@ -0,0 +1,127 @@
+/**
+ * The unified changes tab: one tab, two lenses on "what changed?" — Git
+ * (repository truth: staged/unstaged files, commit box, history) and the
+ * session round (agent truth: every file the model read, wrote, or edited).
+ * Both lenses preview their selections in a shared resizable bottom pane
+ * ({@link DiffPane}); git targets can expand into the dedicated diff tab.
+ * The active lens and the pane height persist in the tab's meta, so the tab
+ * reopens exactly where it was left.
+ */
+import { useState } from 'react'
+import type { TabComponentProps } from '../service.ts'
+import { t } from '../locales.ts'
+import type { SidebarDiffRef } from '../state.ts'
+import { GitLens } from './GitLens.tsx'
+import { SessionLens } from './SessionLens.tsx'
+import { DiffPane, diffTabOf, type ChangesPreview } from './DiffPane.tsx'
+import type { FileOp } from './ops.ts'
+import css from './changes.module.css'
+
+/** The default preview pane height (px) before the first drag. */
+const PANE_HEIGHT_DEFAULT = 300
+
+type Lens = 'git' | 'session'
+
+/** The persisted tab meta (JSON-serializable; rides the layout). */
+interface ChangesMeta {
+  lens?: Lens
+  previewH?: number
+}
+
+export function ChangesTab({ ctx, store, scope, tab, visible, onOpenFile, onOpenDiff }: TabComponentProps) {
+  const meta = (tab.meta ?? {}) as ChangesMeta
+  const [lens, setLens] = useState<Lens>(meta.lens === 'session' ? 'session' : 'git')
+  const [preview, setPreview] = useState<ChangesPreview | null>(null)
+  const [paneHeight, setPaneHeight] = useState<number>(
+    typeof meta.previewH === 'number' && meta.previewH >= 140 ? meta.previewH : PANE_HEIGHT_DEFAULT,
+  )
+
+  /** Persist a meta patch onto the tab (lens choice, pane height). */
+  const patchMeta = (patch: ChangesMeta): void => {
+    ctx.get('betterSidebar')?.updateTab(tab.id, {
+      meta: { ...(tab.meta as ChangesMeta | undefined ?? {}), ...patch },
+    })
+  }
+
+  const chooseLens = (next: Lens): void => {
+    if (next === lens) return
+    setLens(next)
+    patchMeta({ lens: next })
+  }
+
+  /** Preview one git change (worktree file or commit) from the Git lens. */
+  const previewGit = (ref: SidebarDiffRef): void => {
+    setPreview({ kind: 'git', ref })
+  }
+
+  /** Preview one session op (with its best-effort prior content snapshot). */
+  const previewOp = (path: string, op: FileOp, prior: string | undefined): void => {
+    setPreview({ kind: 'op', path, op, prior })
+  }
+
+  const previewKey = (target: ChangesPreview): string => target.kind === 'git'
+    ? (target.ref.kind === 'worktree'
+        ? `git:w:${target.ref.path}:${target.ref.staged ? 's' : 'u'}`
+        : `git:c:${target.ref.hashFull}`)
+    : `op:${target.op.callId}`
+
+  return (
+    <div className={css.root}>
+      <div className={css.lensBar}>
+        <div className={css.lensSwitch} role="group" aria-label={t('changes')}>
+          <button
+            type="button"
+            className={css.lensButton}
+            data-active={lens === 'git' ? 'true' : undefined}
+            aria-pressed={lens === 'git'}
+            onClick={() => { chooseLens('git') }}
+          >
+            {t('changesGitLens')}
+          </button>
+          <button
+            type="button"
+            className={css.lensButton}
+            data-active={lens === 'session' ? 'true' : undefined}
+            aria-pressed={lens === 'session'}
+            onClick={() => { chooseLens('session') }}
+          >
+            {t('changesSessionLens')}
+          </button>
+        </div>
+      </div>
+      {lens === 'git'
+        ? (
+          <GitLens
+            scope={scope}
+            store={store}
+            visible={visible}
+            onOpenFile={onOpenFile ?? (() => { /* no-op */ })}
+            onPreview={previewGit}
+            selectedRef={preview !== null && preview.kind === 'git' ? preview.ref : null}
+          />
+        )
+        : (
+          <SessionLens
+            ctx={ctx}
+            scope={scope}
+            visible={visible}
+            onPreview={previewOp}
+            selectedCallId={preview !== null && preview.kind === 'op' ? preview.op.callId : null}
+          />
+        )}
+      {preview !== null && (
+        <DiffPane
+          key={previewKey(preview)}
+          target={preview}
+          scope={scope}
+          height={paneHeight}
+          onHeightCommit={(height) => { setPaneHeight(height); patchMeta({ previewH: height }) }}
+          onClose={() => { setPreview(null) }}
+          onExpand={() => {
+            if (preview.kind === 'git') onOpenDiff?.(diffTabOf(preview.ref))
+          }}
+        />
+      )}
+    </div>
+  )
+}
diff --git a/src/client/changes/DiffPane.tsx b/src/client/changes/DiffPane.tsx
new file mode 100644
index 0000000..c8ff841
--- /dev/null
+++ b/src/client/changes/DiffPane.tsx
@@ -0,0 +1,313 @@
+/**
+ * The changes tab's shared bottom preview pane: one selected target — a git
+ * worktree change, a commit patch, or a session file op — rendered through
+ * the unified diff stack (the same one the diff tab uses). Git targets load
+ * on demand (refreshable, with the untracked full-addition fallback); op
+ * targets are pure snapshots (diff / read view / error text). The pane is
+ * resizable by drag (clamped; the height commits to the tab's persisted
+ * meta on release) and by keyboard; git targets can expand into a dedicated
+ * diff tab via the shell.
+ */
+import { useEffect, useMemo, useRef, useState, type PointerEvent as ReactPointerEvent } from 'react'
+import { IconCloseOutline16, IconRefreshOutline16, IconRightUpOutline16 } from '@deepseek-ai/dsh-client-ui-primitives'
+import type { SessionScope } from '../api.ts'
+import { api } from '../api.ts'
+import { t } from '../locales.ts'
+import { baseName } from '../paths.ts'
+import { resolveSidebarPath } from '../produced-files.ts'
+import type { SidebarDiffRef, SidebarTab } from '../state.ts'
+import { DiffRows, ReadRows } from '../diff/DiffRows.tsx'
+import { DiffFiles } from '../diff/DiffFiles.tsx'
+import { langOfPath } from '../diff/highlight.ts'
+import { buildDiffSegments, diffLines, diffStats, parseUnifiedDiff, unifiedSegments, type DiffRow } from '../diff/rows.ts'
+import { parseReadLines, type FileOp } from './ops.ts'
+import css from './changes.module.css'
+import diffCss from '../diff/diff.module.css'
+
+/** The drag handle height clamp (px) and keyboard-resize step. */
+const HEIGHT_MIN = 140
+const HEIGHT_STEP = 24
+
+/** What the pane is showing right now. */
+export type ChangesPreview =
+  | { kind: 'git'; ref: SidebarDiffRef }
+  | { kind: 'op'; path: string; op: FileOp; prior?: string }
+
+/** Diff material for one op snapshot: an edit reconstructs the full file
+ *  from the window's known prior content when possible (hunk-style context);
+ *  a write with unknown prior content renders all-added. */
+function diffOf(op: FileOp, prior: string | undefined): readonly DiffRow[] {
+  if (op.kind === 'read') return []
+  if (op.kind === 'edit' && op.edit !== undefined) {
+    const { oldString, newString } = op.edit
+    if (prior !== undefined && prior.includes(oldString)) {
+      const newFile = prior.replace(oldString, newString)
+      return diffLines(prior, newFile)
+    }
+    return diffLines(oldString, newString)
+  }
+  if (op.kind === 'write') {
+    const content = op.content ?? ''
+    const old = prior !== undefined && prior !== content ? prior : undefined
+    return diffLines(old ?? '', content)
+  }
+  return []
+}
+
+/** The diff tab a git preview expands into (the shell owns placement). */
+export function diffTabOf(ref: SidebarDiffRef): SidebarTab {
+  if (ref.kind === 'worktree') {
+    return {
+      id: `diff:w:${encodeURIComponent(ref.worktree ?? '')}:${ref.staged ? 's' : 'u'}:${ref.path}`,
+      type: 'diff',
+      title: baseName(ref.path),
+      diff: ref,
+    }
+  }
+  return {
+    id: `diff:c:${encodeURIComponent(ref.worktree ?? '')}:${ref.hashFull}`,
+    type: 'diff',
+    title: `${ref.hash} ${ref.subject}`,
+    diff: ref,
+  }
+}
+
+export interface DiffPaneProps {
+  target: ChangesPreview
+  scope: SessionScope
+  /** The persisted pane height (px); drag commits a new one upwards. */
+  height: number
+  onHeightCommit: (height: number) => void
+  onClose: () => void
+  /** Expand the current git target into a dedicated diff tab. */
+  onExpand: () => void
+}
+
+export function DiffPane({ target, scope, height, onHeightCommit, onClose, onExpand }: DiffPaneProps) {
+  // ── Git target loading (mirrors the diff tab: staged-side fallback, the
+  //    untracked full-addition fallback, refresh by tick). ─────────────────
+  const [tick, setTick] = useState(0)
+  const [loading, setLoading] = useState(target.kind === 'git')
+  const [error, setError] = useState<string | null>(null)
+  const [diffText, setDiffText] = useState<string | null>(null)
+  const [untracked, setUntracked] = useState<string | undefined>(undefined)
+  const gitRef = target.kind === 'git' ? target.ref : null
+
+  useEffect(() => {
+    if (gitRef === null) return
+    let cancelled = false
+    const paneScope: SessionScope = {
+      sessionId: scope.sessionId,
+      cwd: scope.cwd,
+      ...(gitRef.repoRoot !== undefined ? { repoRoot: gitRef.repoRoot } : {}),
+    }
+    setLoading(true)
+    setError(null)
+    setDiffText(null)
+    setUntracked(undefined)
+    const load = async (): Promise<void> => {
+      try {
+        if (gitRef.kind === 'commit') {
+          const result = await api.gitCommitDiff(paneScope, gitRef.hashFull, gitRef.worktree)
+          if (!cancelled) setDiffText(result.diff)
+          return
+        }
+        let result = await api.gitDiff(paneScope, gitRef.path, gitRef.staged, gitRef.worktree)
+        if (result.diff === '') {
+          // The requested side is empty — try the OTHER side once (the change
+          // may have moved sides after the preview target was minted).
+          const other = await api.gitDiff(paneScope, gitRef.path, !gitRef.staged, gitRef.worktree)
+          if (other.diff !== '') result = other
+        }
+        if (result.diff !== '') {
+          if (!cancelled) setDiffText(result.diff)
+          return
+        }
+        // Empty diff: an untracked file (git diff never lists it) falls back
+        // to a full-file addition from its content.
+        if (gitRef.untracked === true && !gitRef.staged) {
+          const text = await api.fsRead(paneScope, resolveSidebarPath(gitRef.repoRoot ?? gitRef.worktree ?? scope.cwd, gitRef.path))
+          if (!cancelled && text.kind === 'text') {
+            setDiffText('')
+            setUntracked(text.content)
+          }
+          return
+        }
+        if (!cancelled) setDiffText('')
+      } catch (reason) {
+        if (!cancelled) setError(reason instanceof Error ? reason.message : String(reason))
+      } finally {
+        if (!cancelled) setLoading(false)
+      }
+    }
+    void load()
+    return () => { cancelled = true }
+  }, [gitRef, scope.sessionId, scope.cwd, tick])
+
+  // ── Op target material (pure snapshots; the prior content came with the
+  //    target so a running op shows what is already known). ────────────────
+  const op = target.kind === 'op' ? target.op : null
+  const prior = target.kind === 'op' ? target.prior : undefined
+  const opLang = useMemo(() => (target.kind === 'op' ? langOfPath(target.path) : undefined), [target])
+  const opRows = useMemo(() => (op === null ? [] : diffOf(op, prior)), [op, prior])
+  const opSegments = useMemo(() => buildDiffSegments(opRows), [opRows])
+  const opStats = useMemo(() => diffStats(opSegments), [opSegments])
+  const opReadLines = useMemo(
+    () => (op?.kind === 'read' && op.read !== undefined ? parseReadLines(op.read) : []),
+    [op],
+  )
+
+  // Header stats for git targets come off the parsed patch text.
+  const gitStats = useMemo(() => {
+    if (target.kind !== 'git' || diffText === null || diffText === '') return null
+    let added = 0
+    let deleted = 0
+    for (const file of parseUnifiedDiff(diffText).files) {
+      const stats = diffStats(unifiedSegments(file))
+      added += stats.added
+      deleted += stats.deleted
+    }
+    return { added, deleted }
+  }, [target, diffText])
+
+  // ── Resize: drag the top handle; commit on release (persisted by the
+  //    shell). Arrow keys resize by a step for keyboard users. ────────────
+  const [dragHeight, setDragHeight] = useState<number | null>(null)
+  const paneHeight = dragHeight ?? height
+  const clamp = (value: number): number => Math.min(Math.max(value, HEIGHT_MIN), Math.round(window.innerHeight * 0.7))
+  const dragOrigin = useRef<{ y: number; h: number } | null>(null)
+  const onHandleDown = (event: ReactPointerEvent<HTMLDivElement>): void => {
+    event.preventDefault()
+    dragOrigin.current = { y: event.clientY, h: paneHeight }
+    const onMove = (ev: PointerEvent): void => {
+      if (dragOrigin.current === null) return
+      setDragHeight(clamp(dragOrigin.current.h + (dragOrigin.current.y - ev.clientY)))
+    }
+    const onUp = (): void => {
+      window.removeEventListener('pointermove', onMove)
+      window.removeEventListener('pointerup', onUp)
+      dragOrigin.current = null
+      setDragHeight(current => {
+        if (current !== null) onHeightCommit(current)
+        return null
+      })
+    }
+    window.addEventListener('pointermove', onMove)
+    window.addEventListener('pointerup', onUp)
+  }
+
+  const title = target.kind === 'op'
+    ? target.path
+    : target.ref.kind === 'worktree' ? target.ref.path : `${target.ref.hash} ${target.ref.subject}`
+  const stats = gitStats ?? (target.kind === 'op' && op !== null && op.kind !== 'read' && !op.isError ? opStats : null)
+
+  return (
+    <div className={css.diffPane} style={{ height: paneHeight }}>
+      <div
+        className={css.dragHandle}
+        role="separator"
+        aria-orientation="horizontal"
+        aria-label={t('changesResizePreview')}
+        tabIndex={0}
+        onPointerDown={onHandleDown}
+        onKeyDown={(event) => {
+          if (event.key === 'ArrowUp') { event.preventDefault(); onHeightCommit(clamp(paneHeight + HEIGHT_STEP)) }
+          if (event.key === 'ArrowDown') { event.preventDefault(); onHeightCommit(clamp(paneHeight - HEIGHT_STEP)) }
+        }}
+      />
+      <div className={css.diffHead}>
+        {target.kind === 'op' && (
+          <span className={css.diffKind} data-kind={target.op.kind}>
+            {t(target.op.kind === 'read' ? 'changesRead' : target.op.kind === 'write' ? 'changesWrite' : 'changesEdit')}
+          </span>
+        )}
+        {target.kind === 'git' && target.ref.kind === 'worktree' && (
+          <span className={css.diffKind} data-kind="git">{target.ref.staged ? t('staged') : t('unstaged')}</span>
+        )}
+        {target.kind === 'git' && target.ref.kind === 'commit' && (
+          <span className={css.diffKind} data-kind="git">{target.ref.hash}</span>
+        )}
+        <span className={css.diffPath} title={title}>{title}</span>
+        {stats !== null && (stats.added > 0 || stats.deleted > 0) && (
+          <span className={css.diffStats}>
+            {stats.added > 0 && <span className={diffCss.statAdd}>+{String(stats.added)}</span>}
+            {stats.deleted > 0 && <span className={diffCss.statDel}>−{String(stats.deleted)}</span>}
+          </span>
+        )}
+        {target.kind === 'git' && (
+          <>
+            <button
+              type="button"
+              className={css.iconButton}
+              aria-label={t('refresh')}
+              title={t('refresh')}
+              disabled={loading}
+              onClick={() => { setTick(value => value + 1) }}
+            >
+              <IconRefreshOutline16 size={14} />
+            </button>
+            <button
+              type="button"
+              className={css.iconButton}
+              aria-label={t('changesOpenDiffTab')}
+              title={t('changesOpenDiffTab')}
+              onClick={onExpand}
+            >
+              <IconRightUpOutline16 size={14} />
+            </button>
+          </>
+        )}
+        <button
+          type="button"
+          className={css.iconButton}
+          aria-label={t('changesClosePreview')}
+          title={t('changesClosePreview')}
+          onClick={onClose}
+        >
+          <IconCloseOutline16 size={14} />
+        </button>
+      </div>
+      {target.kind === 'op' && op !== null && op.isError
+        ? (
+          <div className={css.paneBody}>
+            <div className={css.readError} role="alert">
+              {op.errorText ?? t('changesError')}
+            </div>
+          </div>
+        )
+        : target.kind === 'op' && op !== null && op.kind === 'read'
+          ? (
+            <div className={css.paneBody}>
+              <ReadRows lines={opReadLines} lang={opLang} />
+            </div>
+          )
+          : target.kind === 'op'
+            ? (
+              <div className={css.paneBody}>
+                {op !== null && op.kind === 'write'
+                  && prior === undefined
+                  && <div className={css.priorUnknown}>{t('changesPriorUnknown')}</div>}
+                <DiffRows key={target.op.callId} segments={opSegments} lang={opLang} />
+              </div>
+            )
+            : loading
+              ? <div className={css.paneBody}><div className={css.gitPlaceholder}>{t('loading')}</div></div>
+              : error !== null
+                ? <div className={css.paneBody}><div className={css.gitError}>{t('diffLoadError')}: {error}</div></div>
+                : (
+                  <div className={css.paneBody}>
+                    {diffText !== null && diffText !== '' && (
+                      <DiffFiles
+                        diff={diffText}
+                        untrackedPath={untracked !== undefined && target.ref.kind === 'worktree' ? target.ref.path : undefined}
+                        untrackedContent={untracked}
+                      />
+                    )}
+                    {diffText === '' && untracked === undefined && (
+                      <div className={css.gitEmpty}>{t('diffEmpty')}</div>
+                    )}
+                  </div>
+                )}
+    </div>
+  )
+}
diff --git a/src/client/GitView.tsx b/src/client/changes/GitLens.tsx
similarity index 88%
rename from src/client/GitView.tsx
rename to src/client/changes/GitLens.tsx
index 773ca29..d343ff1 100644
--- a/src/client/GitView.tsx
+++ b/src/client/changes/GitLens.tsx
@@ -1,32 +1,33 @@
 /**
- * The source-control panel: status list (staged vs unstaged), stage/unstage,
- * commit with a message box, branch switch, and a VSCode-like history — rows
- * carry branch decorations, author and relative time. Clicking a changed
- * file or a history row opens a dedicated diff TAB (see {@link DiffTab}),
- * placed below the git pane on first use. File rows and history rows open a
- * right-click context menu with advanced operations (open in editor, discard,
- * revert, cherry-pick, copy paths/hashes). Refresh is manual + on mount/
- * focus. While visible it polls lightweight porcelain state so model-authored
- * file changes appear without a manual refresh.
+ * The Git lens of the changes tab: repository truth — status list (staged vs
+ * unstaged), stage/unstage, commit with a message box, branch switch, and a
+ * VSCode-like history with branch decorations, author and relative time.
+ * Clicking a changed file or a history row previews it in the tab's shared
+ * bottom pane (see {@link DiffPane}); rows carry right-click context menus
+ * with advanced operations (open in editor, discard, revert, cherry-pick,
+ * copy paths/hashes). Refresh is manual + on mount/focus. While visible it
+ * polls lightweight porcelain state so model-authored file changes appear
+ * without a manual refresh. Everything here is the former standalone git
+ * panel, re-homed as a lens.
  */
 import { useCallback, useEffect, useRef, useState, type MouseEvent, type ReactNode } from 'react'
 import {
   Button, IconBranchOutline16, IconCodeOutline16, IconCopyOutline16, IconRefreshOutline16,
   IconTrashOutline16, Input, Menu, Modal, writeClipboard,
 } from '@deepseek-ai/dsh-client-ui-primitives'
-import type { GitLogEntry, GitStatusEntry, GitStatusResult, GitWorktree, SessionScope } from './api.ts'
-import { api } from './api.ts'
-import { isWithinWorkspace, relativeTo } from './paths.ts'
-import { resolveSidebarPath } from './produced-files.ts'
-import { relativeTime, t } from './locales.ts'
-import type { SidebarStore, SidebarTab } from './state.ts'
-import css from './sidebar.module.css'
+import type { GitLogEntry, GitStatusEntry, GitStatusResult, GitWorktree, SessionScope } from '../api.ts'
+import { api } from '../api.ts'
+import { baseName, isWithinWorkspace, relativeTo } from '../paths.ts'
+import { resolveSidebarPath } from '../produced-files.ts'
+import { relativeTime, t } from '../locales.ts'
+import type { SidebarDiffRef, SidebarStore } from '../state.ts'
+import css from './changes.module.css'
 
 /** The XY status letters a row badge shows (X = index, Y = worktree). */
 function badgeOf(entry: GitStatusEntry): string {
   const index = entry.xy[0]
-  const worktree = entry.xy[1]
   if (index !== undefined && index !== ' ' && index !== '?') return index
+  const worktree = entry.xy[1]
   if (worktree !== undefined && worktree !== ' ' && worktree !== '?') return worktree
   return '?'
 }
@@ -51,12 +52,6 @@ function isUntracked(entry: GitStatusEntry): boolean {
   return badgeOf(entry) === '?'
 }
 
-/** The last path segment (tab title for a file's diff). */
-function baseName(path: string): string {
-  const at = Math.max(path.lastIndexOf('/'), path.lastIndexOf('\\'))
-  return at === -1 ? path : path.slice(at + 1)
-}
-
 /** The ref names of one log row's decorations (`HEAD -> main` → `main`), deduped. */
 function refNames(refs: string): string[] {
   return [...new Set(
@@ -81,17 +76,21 @@ interface ConfirmState {
  *  floods the panel at once (the end of the log is reached by paging). */
 const LOG_BATCH = 20
 
-export function GitView(props: {
+export interface GitLensProps {
   scope: SessionScope
   /** The sidebar store: reads the `workspaceFence` pref (see the open guard below). */
   store: SidebarStore
   onOpenFile: (path: string) => void
-  /** Open a diff tab (the shell places it below the git pane on first use). */
-  onOpenDiff: (tab: SidebarTab) => void
+  /** Preview one change in the shared bottom pane (worktree or commit ref). */
+  onPreview: (ref: SidebarDiffRef) => void
+  /** The ref currently previewed (row highlight); null when the pane is closed. */
+  selectedRef: SidebarDiffRef | null
   /** Poll only while the tab is actually visible. */
   visible: boolean
-}) {
-  const { scope, store, onOpenFile, onOpenDiff, visible } = props
+}
+
+export function GitLens(props: GitLensProps) {
+  const { scope, store, onOpenFile, onPreview, selectedRef, visible } = props
   const [status, setStatus] = useState<GitStatusResult | null>(null)
   const [worktrees, setWorktrees] = useState<GitWorktree[]>([])
   const [selectedWorktree, setSelectedWorktree] = useState<string | undefined>()
@@ -122,8 +121,8 @@ export function GitView(props: {
    *  avoids a spurious full refresh on every auto-select (the very state
    *  change refresh writes back via setSelectedWorktree would recreate the
    *  callback and re-trigger the mount effect — an N→N+1 fetch loop). */
-  const selectedRef = useRef<string | undefined>(undefined)
-  useEffect(() => { selectedRef.current = selectedWorktree }, [selectedWorktree])
+  const chosenPathRef = useRef<string | undefined>(undefined)
+  useEffect(() => { chosenPathRef.current = selectedWorktree }, [selectedWorktree])
 
   const gitScope: SessionScope = repoRoot === undefined ? scope : { ...scope, repoRoot }
 
@@ -164,8 +163,8 @@ export function GitView(props: {
       const listed = await api.gitWorktrees(scope)
       if (generation !== refreshGeneration.current) return
       setWorktrees(listed)
-      const selectedStillExists = listed.some(entry => entry.path === selectedRef.current)
-      let target = selectedStillExists ? selectedRef.current : listed.find(entry => entry.current)?.path
+      const selectedStillExists = listed.some(entry => entry.path === chosenPathRef.current)
+      let target = selectedStillExists ? chosenPathRef.current : listed.find(entry => entry.current)?.path
       // DSH and other coding agents commonly create one linked checkout while
       // the session remains rooted at the clean primary checkout. Select that
       // checkout automatically only when the choice is unambiguous.
@@ -176,12 +175,12 @@ export function GitView(props: {
           ? dirtyLinked[0]!.path
           : current?.path
       }
-      const targetChanged = target !== selectedRef.current
+      const targetChanged = target !== chosenPathRef.current
       if (targetChanged) {
         // Changing the automatically selected checkout invalidates any direct
         // target refresh that may still be resolving for the previous one.
         generation = refreshGeneration.current += 1
-        selectedRef.current = target
+        chosenPathRef.current = target
         setSelectedWorktree(target)
         // Remove rows owned by the previous checkout immediately: keeping them
         // interactive while the target changes could apply a destructive action
@@ -214,7 +213,7 @@ export function GitView(props: {
     refreshGeneration.current += 1
     refreshInFlight.current = false
     worktreeChosenByUser.current = false
-    selectedRef.current = undefined
+    chosenPathRef.current = undefined
     setSelectedWorktree(undefined)
   }, [scope.sessionId, scope.cwd])
   useEffect(() => { void refresh() }, [refresh])
@@ -223,7 +222,7 @@ export function GitView(props: {
    *  checkout-derived surface before destructive history actions can run. */
   const chooseWorktree = (target: string): void => {
     worktreeChosenByUser.current = true
-    selectedRef.current = target
+    chosenPathRef.current = target
     setSelectedWorktree(target)
     setStatus(null)
     setBranchNames([])
@@ -248,7 +247,7 @@ export function GitView(props: {
     // own worktree list is empty); keep the current linked-checkout choice
     // unless it does not belong to the new repository.
     const generation = refreshGeneration.current += 1
-    void refreshTarget(selectedRef.current ?? '', { loading: true, generation })
+    void refreshTarget(chosenPathRef.current ?? '', { loading: true, generation })
   }
   useEffect(() => {
     if (!visible) return
@@ -260,42 +259,49 @@ export function GitView(props: {
   const loadMoreLog = async (): Promise<void> => {
     if (logLoadingMore || logEnded) return
     const generation = refreshGeneration.current
-    const target = selectedRef.current
+    const target = chosenPathRef.current
     setLogLoadingMore(true)
     try {
       const next = await api.gitLog(gitScope, LOG_BATCH, logEntries.length, target)
       // A worktree switch clears the old history and increments generation.
       // Never append a late page from that checkout into the new one.
-      if (generation !== refreshGeneration.current || target !== selectedRef.current) return
+      if (generation !== refreshGeneration.current || target !== chosenPathRef.current) return
       setLogEntries(entries => [...entries, ...next])
       if (next.length < LOG_BATCH) setLogEnded(true)
     } catch (reason) {
-      if (generation === refreshGeneration.current && target === selectedRef.current) {
+      if (generation === refreshGeneration.current && target === chosenPathRef.current) {
         setCommitError(`${t('historyLoadError')}: ${reason instanceof Error ? reason.message : String(reason)}`)
       }
     } finally {
-      if (generation === refreshGeneration.current && target === selectedRef.current) setLogLoadingMore(false)
+      if (generation === refreshGeneration.current && target === chosenPathRef.current) setLogLoadingMore(false)
     }
   }
 
-  /** The diff tab for one changed file (one tab per path+side; same id = focused). */
-  const openWorktreeDiff = (entry: GitStatusEntry, staged: boolean): void => {
-    onOpenDiff({
-      id: `diff:w:${encodeURIComponent(selectedWorktree ?? '')}:${staged ? 's' : 'u'}:${entry.path}`,
-      type: 'diff',
-      title: baseName(entry.path),
-      diff: { kind: 'worktree', path: entry.path, staged, untracked: isUntracked(entry), worktree: selectedWorktree, repoRoot },
-    })
-  }
+  /** The preview ref for one changed file (one ref per path+side). */
+  const worktreeRefOf = (entry: GitStatusEntry, staged: boolean): SidebarDiffRef => ({
+    kind: 'worktree',
+    path: entry.path,
+    staged,
+    untracked: isUntracked(entry),
+    worktree: selectedWorktree,
+    repoRoot,
+  })
 
-  /** The diff tab for one commit (one tab per commit). */
-  const openCommitDiff = (entry: GitLogEntry): void => {
-    onOpenDiff({
-      id: `diff:c:${encodeURIComponent(selectedWorktree ?? '')}:${entry.hashFull}`,
-      type: 'diff',
-      title: `${entry.hash} ${entry.subject}`,
-      diff: { kind: 'commit', hash: entry.hash, hashFull: entry.hashFull, subject: entry.subject, worktree: selectedWorktree, repoRoot },
-    })
+  /** The preview ref for one commit. */
+  const commitRefOf = (entry: GitLogEntry): SidebarDiffRef => ({
+    kind: 'commit',
+    hash: entry.hash,
+    hashFull: entry.hashFull,
+    subject: entry.subject,
+    worktree: selectedWorktree,
+    repoRoot,
+  })
+
+  /** Whether a worktree row is the one currently previewed. */
+  const isPreviewedWorktree = (entry: GitStatusEntry, staged: boolean): boolean => {
+    if (selectedRef === null || selectedRef.kind !== 'worktree') return false
+    return selectedRef.path === entry.path && selectedRef.staged === staged
+      && (selectedRef.worktree ?? '') === (selectedWorktree ?? '')
   }
 
   const stageEntry = async (entry: GitStatusEntry, staged: boolean): Promise<void> => {
@@ -387,16 +393,21 @@ export function GitView(props: {
   const unstagedEntries = (status?.entries ?? []).filter(isUnstagedEntry)
 
   const renderEntry = (entry: GitStatusEntry, staged: boolean): ReactNode => {
+    const selected = isPreviewedWorktree(entry, staged)
     return (
-      <div key={`${staged ? 's' : 'u'}:${entry.path}`} className={css.gitRow}>
+      <div
+        key={`${staged ? 's' : 'u'}:${entry.path}`}
+        className={css.gitRow}
+        data-selected={selected ? 'true' : undefined}
+      >
         <button
           type="button"
           className={css.gitRowMain}
           title={entry.path}
-          onClick={() => { openWorktreeDiff(entry, staged) }}
+          onClick={() => { onPreview(worktreeRefOf(entry, staged)) }}
           onContextMenu={(event) => { openFileMenu(event, entry, staged) }}
         >
-          <span className={css.gitBadge}>{badgeOf(entry)}</span>
+          <span className={css.gitBadge} data-letter={badgeOf(entry)}>{badgeOf(entry)}</span>
           <span className={css.gitName}>{entry.path}</span>
         </button>
         <button
@@ -531,12 +542,13 @@ export function GitView(props: {
                 role="button"
                 tabIndex={0}
                 className={css.gitLogRow}
+                data-selected={selectedRef?.kind === 'commit' && selectedRef.hashFull === entry.hashFull ? 'true' : undefined}
                 title={`${entry.author} · ${entry.date}\n${entry.hashFull}`}
-                onClick={() => { openCommitDiff(entry) }}
+                onClick={() => { onPreview(commitRefOf(entry)) }}
                 onKeyDown={(event) => {
                   if (event.key === 'Enter' || event.key === ' ') {
                     event.preventDefault()
-                    openCommitDiff(entry)
+                    onPreview(commitRefOf(entry))
                   }
                 }}
                 onContextMenu={(event) => { openHistoryMenu(event, entry) }}
@@ -650,7 +662,7 @@ export function GitView(props: {
               if (target === null) return
               setHistoryMenu(null)
               if (id === 'view') {
-                openCommitDiff(target.entry)
+                onPreview(commitRefOf(target.entry))
                 return
               }
               if (id === 'copyShort') {
diff --git a/src/client/changes/SessionLens.tsx b/src/client/changes/SessionLens.tsx
new file mode 100644
index 0000000..298bde7
--- /dev/null
+++ b/src/client/changes/SessionLens.tsx
@@ -0,0 +1,127 @@
+/**
+ * The session lens of the changes tab: agent truth — every file the model
+ * read, wrote, or edited in this session (folded from the session event
+ * log), grouped by file, newest first, with kind filters. Clicking an op
+ * previews it in the tab's shared bottom pane (see {@link DiffPane}): writes
+ * and edits as line diffs, reads as a line-numbered content view, failures
+ * as their real error text. Live `tool/call` / `tool/result` events append
+ * while the tab is visible (bounded; paused and caught up when hidden).
+ */
+import { useEffect, useMemo, useRef, useState, type ReactNode } from 'react'
+import type { SidebarSessionEvent } from '../../context-types.ts'
+import type { Context } from '../../context-types.ts'
+import type { SessionScope } from '../api.ts'
+import { relativeTime, t } from '../locales.ts'
+import { extractFileOps, groupByFile, knownContentBefore, type FileOp, type FileOpKind } from './ops.ts'
+import { formatBytes } from '../diff/rows.ts'
+import css from './changes.module.css'
+
+/** Cap on accumulated events: the lens shows the recent window, not eternity. */
+const EVENTS_CAP = 4000
+
+/** The op-kind filter chips: 'all' or one concrete kind. */
+type OpFilter = 'all' | FileOpKind
+
+export interface SessionLensProps {
+  ctx: Context
+  scope: SessionScope
+  /** Preview one op in the shared bottom pane (with its best-effort prior content). */
+  onPreview: (path: string, op: FileOp, prior: string | undefined) => void
+  /** The op currently previewed (row highlight); null when the pane is closed. */
+  selectedCallId: string | null
+  /** Fold events only while the tab is actually visible. */
+  visible: boolean
+}
+
+export function SessionLens({ ctx, scope, onPreview, selectedCallId, visible }: SessionLensProps) {
+  // The event log snapshot seeds the lens once; live tool/call and
+  // tool/result events append (bounded) and re-extract while visible.
+  const eventsRef = useRef<readonly SidebarSessionEvent[] | null>(null)
+  if (eventsRef.current === null) {
+    eventsRef.current = ctx.sessions.get(scope.sessionId)?.events ?? []
+  }
+  const [tick, setTick] = useState(0)
+  useEffect(() => {
+    if (typeof ctx.on !== 'function') return
+    const off = ctx.on('session/event', (session: unknown, event: SidebarSessionEvent) => {
+      const sessionId = (session as { id?: unknown } | null)?.id
+      if (sessionId !== scope.sessionId) return
+      if (event.type !== 'tool/call' && event.type !== 'tool/result') return
+      const list = [...eventsRef.current ?? [], event]
+      eventsRef.current = list.length > EVENTS_CAP ? list.slice(list.length - EVENTS_CAP) : list
+      if (visible) setTick(value => value + 1)
+    })
+    return () => { off() }
+  }, [ctx, scope.sessionId, visible])
+  // Becoming visible again catches up on events appended while paused.
+  useEffect(() => { if (visible) setTick(value => value + 1) }, [visible])
+
+  const ops = useMemo(() => extractFileOps(eventsRef.current ?? []), [tick])
+  const [filter, setFilter] = useState<OpFilter>('all')
+  const filteredOps = useMemo(
+    () => (filter === 'all' ? ops : ops.filter(op => op.kind === filter)),
+    [ops, filter],
+  )
+  const groups = useMemo(() => groupByFile(filteredOps), [filteredOps])
+  const counts = useMemo(() => {
+    const map = new Map<FileOpKind, number>([['read', 0], ['write', 0], ['edit', 0]])
+    for (const op of ops) map.set(op.kind, (map.get(op.kind) ?? 0) + 1)
+    return map
+  }, [ops])
+
+  const chip = (value: OpFilter, label: string, count: number): ReactNode => (
+    <button
+      type="button"
+      key={value}
+      className={css.filterChip}
+      data-active={filter === value ? 'true' : undefined}
+      onClick={() => { setFilter(value) }}
+      aria-pressed={filter === value}
+    >
+      {label}{value !== 'all' ? ` ${String(count)}` : ''}
+    </button>
+  )
+
+  return (
+    <div className={css.session}>
+      <div className={css.filterRow} role="group" aria-label={t('changesSessionLens')}>
+        {chip('all', t('changesFilterAll'), ops.length)}
+        {chip('write', t('changesWrite'), counts.get('write') ?? 0)}
+        {chip('edit', t('changesEdit'), counts.get('edit') ?? 0)}
+        {chip('read', t('changesRead'), counts.get('read') ?? 0)}
+      </div>
+      <div className={css.sessionList}>
+        {ops.length === 0 && <div className={css.empty}>{t('changesSessionEmpty')}</div>}
+        {ops.length > 0 && filteredOps.length === 0 && <div className={css.empty}>{t('changesFilterEmpty')}</div>}
+        {[...groups.entries()].map(([path, fileOps]) => (
+          <div key={path} className={css.fileGroup}>
+            <div className={css.filePath} title={path}>{path}</div>
+            {fileOps.map(op => (
+              <button
+                type="button"
+                key={op.callId}
+                className={css.opRow}
+                data-op-kind={op.kind}
+                data-op-error={op.isError ? 'true' : undefined}
+                data-selected={selectedCallId === op.callId ? 'true' : undefined}
+                onClick={() => { onPreview(path, op, knownContentBefore(ops, path, op)) }}
+              >
+                <span className={css.opKind} data-kind={op.kind}>
+                  {t(op.kind === 'read' ? 'changesRead' : op.kind === 'write' ? 'changesWrite' : 'changesEdit')}
+                </span>
+                <span className={css.opTime}>{relativeTime(new Date(op.time).toISOString())}</span>
+                {op.running && <span className={css.opFlag}>{t('changesRunning')}</span>}
+                {op.isError && <span className={css.opFlagError}>{t('changesError')}</span>}
+                {op.kind !== 'read' && !op.isError && (
+                  <span className={css.opSize}>
+                    {formatBytes(new Blob([op.edit?.newString ?? op.content ?? '']).size)}
+                  </span>
+                )}
+              </button>
+            ))}
+          </div>
+        ))}
+      </div>
+    </div>
+  )
+}
diff --git a/src/client/changes/changes.module.css b/src/client/changes/changes.module.css
new file mode 100644
index 0000000..17e83fa
--- /dev/null
+++ b/src/client/changes/changes.module.css
@@ -0,0 +1,386 @@
+/* The unified changes tab: lens switcher + Git lens + session lens + the
+   shared preview pane. Semantic --dsw-alias tokens only (skin contract).
+   The git lens styles moved here from sidebar.module.css when the git panel
+   became a lens of this tab; the generic placeholder/empty/error trio stays
+   duplicated in both modules (the diff tab still owns its copy). */
+
+.root { display: flex; flex-direction: column; min-height: 0; height: 100%; background: var(--dsw-alias-bg-base); color: var(--dsw-alias-label-primary); font-size: 12px; }
+
+/* ── Lens switcher ─────────────────────────────────────────────────────── */
+
+.lensBar { flex: none; display: flex; align-items: center; padding: 8px 8px 4px 12px; }
+.lensSwitch { display: inline-flex; gap: 2px; padding: 2px; border: 1px solid var(--dsw-alias-border-l2); border-radius: 8px; }
+.lensButton { border: 0; border-radius: 6px; padding: 2px 10px; background: transparent; color: var(--dsw-alias-label-secondary); font: var(--dsw-font-xxxs-strong-11); cursor: pointer; }
+.lensButton:hover { color: var(--dsw-alias-label-primary); }
+.lensButton[data-active='true'] { background: var(--dsw-alias-interactive-bg-active); color: var(--dsw-alias-label-primary); }
+
+/* ── Git lens (the former git panel) ───────────────────────────────────── */
+
+.git {
+  flex: 1;
+  min-height: 0;
+  min-width: 0;
+  display: flex;
+  flex-direction: column;
+  overflow-y: auto;
+  /* Tab pages never scroll horizontally: content wraps or truncates to the
+     panel width instead of panning sideways. */
+  overflow-x: hidden;
+}
+
+.gitHeader {
+  flex: none;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  height: 36px;
+  padding: 0 8px 0 12px;
+}
+
+.gitWorktreeRow {
+  flex: none;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 6px 8px 0 12px;
+}
+
+.gitWorktreeLabel {
+  flex: none;
+  color: var(--dsw-alias-label-tertiary);
+  font: var(--dsw-font-xxxs-11);
+}
+
+.gitBranchSelect {
+  flex: 1;
+  min-width: 0;
+  height: 26px;
+  padding: 0 6px;
+  border: 1px solid var(--dsw-alias-border-l2);
+  border-radius: 6px;
+  background: var(--dsw-alias-bg-base);
+  color: var(--dsw-alias-label-primary);
+  font: var(--dsw-font-xxs-12);
+}
+
+.gitSection {
+  border-top: 1px solid var(--dsw-alias-border-l1);
+}
+
+.gitSectionHeader {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 6px 12px 4px;
+  font: var(--dsw-font-xxxs-strong-11);
+  color: var(--dsw-alias-label-tertiary);
+  text-transform: uppercase;
+}
+
+.gitLink {
+  border: none;
+  background: transparent;
+  font: var(--dsw-font-xxxs-11);
+  color: var(--dsw-alias-brand-primary);
+  cursor: pointer;
+  padding: 0;
+}
+
+.gitLink:hover:not(:disabled) {
+  text-decoration: underline;
+}
+
+.gitLink:disabled {
+  opacity: 0.4;
+  cursor: default;
+}
+
+.gitRow {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  min-height: 34px;
+  margin: 0 6px;
+  padding: 0 8px;
+  border-radius: 8px;
+  animation: dsh-row-in 150ms var(--ds-ease-in-out);
+}
+
+.gitRow:hover {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.gitRow[data-selected='true'] {
+  background: var(--dsw-alias-interactive-bg-active);
+}
+
+.gitRowMain {
+  flex: 1;
+  min-width: 0;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  border: none;
+  background: transparent;
+  padding: 3px 0;
+  cursor: pointer;
+  text-align: left;
+}
+
+.gitBadge {
+  flex: none;
+  width: 20px;
+  height: 16px;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  border-radius: 4px;
+  font: var(--dsw-font-xxxs-strong-11);
+  background: var(--dsw-alias-interactive-bg-hover);
+  color: var(--dsw-alias-label-secondary);
+}
+
+/* Status-letter tint: A added / D deleted / M·R modified / C·U conflicts. */
+.gitBadge[data-letter='A'] { color: var(--dsw-alias-state-success-primary); }
+.gitBadge[data-letter='D'] { color: var(--dsw-alias-state-error-primary); }
+.gitBadge[data-letter='M'], .gitBadge[data-letter='R'] { color: var(--dsw-alias-state-business-primary); }
+.gitBadge[data-letter='C'], .gitBadge[data-letter='U'] { color: var(--dsw-alias-state-warn-primary); }
+
+.gitName {
+  flex: 1;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  font: var(--dsw-font-s-14);
+  color: var(--dsw-alias-label-primary);
+}
+
+.gitEmpty {
+  padding: 4px 12px 8px;
+  font: var(--dsw-font-xxs-12);
+  color: var(--dsw-alias-label-tertiary);
+}
+
+.gitPlaceholder {
+  padding: 16px;
+  font: var(--dsw-font-xxs-12);
+  color: var(--dsw-alias-label-tertiary);
+  text-align: center;
+}
+
+.gitError {
+  padding: 8px 12px;
+  font: var(--dsw-font-xxs-12);
+  color: var(--dsw-alias-state-error-primary);
+  white-space: pre-wrap;
+}
+
+.gitConfirmDesc {
+  margin: 0;
+  font: var(--dsw-font-s-14);
+  color: var(--dsw-alias-label-primary);
+  white-space: pre-wrap;
+}
+
+.gitCommit {
+  display: flex;
+  gap: 6px;
+  padding: 8px 12px;
+  border-top: 1px solid var(--dsw-alias-border-l1);
+  align-items: center;
+}
+
+.gitCommitInput {
+  flex: 1;
+  min-width: 0;
+}
+
+.gitCommitButton {
+  flex: none;
+  height: 26px;
+  padding: 0 12px;
+  border: none;
+  border-radius: 6px;
+  background: var(--dsw-alias-button-primary-fill);
+  color: var(--dsw-alias-label-primary-inverted);
+  font: var(--dsw-font-xxs-strong-12);
+  cursor: pointer;
+}
+
+.gitCommitButton:hover:not(:disabled) {
+  background: var(--dsw-alias-button-primary-hover);
+}
+
+.gitCommitButton:disabled {
+  opacity: 0.45;
+  cursor: default;
+}
+
+/* A history row: line 1 = hash + subject, line 2 = ref badges + author/date
+   (badges live on the second line so they never crowd the subject). */
+.gitLogRow {
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+  padding: 5px 12px;
+  cursor: pointer;
+  border-radius: 8px;
+}
+
+.gitLogRow:hover {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.gitLogRow[data-selected='true'] {
+  background: var(--dsw-alias-interactive-bg-active);
+}
+
+.gitLogLine1 {
+  display: flex;
+  align-items: baseline;
+  gap: 8px;
+  min-width: 0;
+}
+
+.gitLogHash {
+  flex: none;
+  font: var(--dsw-font-markdown-code-block-small);
+  color: var(--dsw-alias-label-tertiary);
+}
+
+.gitLogLine2 {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  min-width: 0;
+  flex-wrap: wrap;
+}
+
+.gitLogRef {
+  flex: none;
+  padding: 0 5px;
+  border: 1px solid var(--dsw-alias-border-l2);
+  border-radius: 999px;
+  font: var(--dsw-font-xxxs-strong-11);
+  color: var(--dsw-alias-brand-primary);
+  white-space: nowrap;
+}
+
+.gitLogSubject {
+  flex: 1;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  font: var(--dsw-font-s-14);
+  color: var(--dsw-alias-label-primary);
+}
+
+.gitLogMeta {
+  font: var(--dsw-font-xxxs-11);
+  color: var(--dsw-alias-label-tertiary);
+}
+
+.gitLogMore {
+  display: block;
+  width: calc(100% - 24px);
+  margin: 4px 12px 8px;
+  padding: 6px 0;
+  border: 1px solid var(--dsw-alias-border-l2);
+  border-radius: 6px;
+  background: transparent;
+  font: var(--dsw-font-xxs-12);
+  color: var(--dsw-alias-label-secondary);
+  cursor: pointer;
+}
+
+.gitLogMore:hover:not(:disabled) {
+  background: var(--dsw-alias-interactive-bg-hover);
+  color: var(--dsw-alias-label-primary);
+}
+
+.gitLogMore:disabled {
+  opacity: 0.5;
+  cursor: default;
+}
+
+/* ── Session lens (this round's files) ─────────────────────────────────── */
+
+.session { flex: 1; min-height: 0; display: flex; flex-direction: column; }
+
+.filterRow { flex: none; display: flex; gap: 4px; padding: 2px 8px 6px 12px; flex-wrap: wrap; }
+.filterChip { border: 1px solid var(--dsw-alias-border-l2); border-radius: 999px; padding: 1px 8px; background: transparent; color: var(--dsw-alias-label-secondary); font: var(--dsw-font-xxxs-11); cursor: pointer; }
+.filterChip:hover { color: var(--dsw-alias-label-primary); background: var(--dsw-alias-interactive-bg-hover); }
+.filterChip[data-active='true'] { background: var(--dsw-alias-interactive-bg-active); color: var(--dsw-alias-label-primary); border-color: transparent; }
+
+.sessionList { flex: 1; min-height: 0; overflow-y: auto; padding: 0 6px 10px; }
+.empty { color: var(--dsw-alias-label-tertiary); padding: 24px 8px; text-align: center; }
+
+.fileGroup { margin-bottom: 8px; }
+.filePath { display: block; color: var(--dsw-alias-label-secondary); font-family: var(--ds-font-family-code, monospace); font-size: 11px; padding: 2px 4px; word-break: break-all; }
+.opRow { display: flex; align-items: center; gap: 6px; width: 100%; border: 0; border-radius: 6px; background: transparent; color: var(--dsw-alias-label-primary); font: inherit; font-size: 11px; padding: 3px 5px; cursor: pointer; text-align: left; }
+.opRow:hover { background: var(--dsw-alias-interactive-bg-hover); }
+.opRow[data-selected='true'] { background: var(--dsw-alias-interactive-bg-active); }
+.opKind { border-radius: 4px; font-size: 10px; line-height: 16px; padding: 0 5px; background: var(--dsw-alias-interactive-bg-hover); color: var(--dsw-alias-label-secondary); flex: none; }
+.opKind[data-kind='write'] { color: var(--dsw-alias-state-success-primary); }
+.opKind[data-kind='edit'] { color: var(--dsw-alias-state-business-primary); }
+.opTime { color: var(--dsw-alias-label-tertiary); font-size: 10px; flex: none; }
+.opFlag { color: var(--dsw-alias-state-business-primary); font-size: 10px; flex: none; }
+.opFlagError { color: var(--dsw-alias-state-error-primary); font-size: 10px; flex: none; }
+.opSize { margin-left: auto; color: var(--dsw-alias-label-tertiary); font-size: 10px; flex: none; }
+
+/* ── Shared preview pane ───────────────────────────────────────────────── */
+
+.diffPane { border-top: 1px solid var(--dsw-alias-border-l1); display: flex; flex-direction: column; flex: none; min-height: 0; }
+.dragHandle { flex: none; height: 8px; cursor: ns-resize; position: relative; background: var(--dsw-alias-bg-base); }
+.dragHandle::after { content: ''; position: absolute; left: calc(50% - 18px); top: 3px; width: 36px; height: 2px; border-radius: 1px; background: var(--dsw-alias-border-l2); }
+.dragHandle:hover::after, .dragHandle:focus-visible::after { background: var(--dsw-alias-state-business-primary); }
+.diffHead { display: flex; align-items: center; gap: 6px; padding: 3px 8px 3px 10px; border-bottom: 1px solid var(--dsw-alias-border-l1); }
+.diffKind { flex: none; border-radius: 4px; font-size: 10px; line-height: 16px; padding: 0 5px; background: var(--dsw-alias-interactive-bg-hover); color: var(--dsw-alias-label-secondary); }
+.diffKind[data-kind='git'] { color: var(--dsw-alias-brand-primary); }
+.diffKind[data-kind='write'] { color: var(--dsw-alias-state-success-primary); }
+.diffKind[data-kind='edit'] { color: var(--dsw-alias-state-business-primary); }
+.diffPath { flex: 1; font-family: var(--ds-font-family-code, monospace); font-size: 11px; word-break: break-all; color: var(--dsw-alias-label-primary); min-width: 0; }
+.diffStats { flex: none; display: inline-flex; gap: 5px; font-size: 10px; font-family: var(--ds-font-family-code, monospace); }
+
+.iconButton {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 24px;
+  height: 24px;
+  padding: 0;
+  border: none;
+  border-radius: 6px;
+  background: transparent;
+  color: var(--dsw-alias-label-secondary);
+  cursor: pointer;
+  flex: none;
+}
+.iconButton:hover:not(:disabled) { background: var(--dsw-alias-interactive-bg-hover); color: var(--dsw-alias-label-primary); }
+.iconButton:disabled { opacity: 0.4; cursor: default; }
+
+.paneBody { flex: 1; min-height: 0; overflow-y: auto; }
+.readError { color: var(--dsw-alias-state-error-primary); border-left: 3px solid var(--dsw-alias-state-error-primary); border-radius: 0 6px 6px 0; margin: 6px 8px; padding: 6px 10px; white-space: pre-wrap; word-break: break-word; }
+.priorUnknown { color: var(--dsw-alias-label-tertiary); font-size: 10px; padding: 3px 10px; }
+
+/* ── Shared bits ───────────────────────────────────────────────────────── */
+
+/* Mount fade for rows (the app's session-row reveal). */
+@keyframes dsh-row-in {
+  from { opacity: 0; }
+}
+
+/* Keyboard focus rings match the shared sidebar convention. */
+.gitLink:focus-visible, .gitRowMain:focus-visible, .gitLogRow:focus-visible,
+.gitCommitButton:focus-visible, .gitLogMore:focus-visible, .gitBranchSelect:focus-visible,
+.lensButton:focus-visible, .filterChip:focus-visible, .iconButton:focus-visible,
+.dragHandle:focus-visible {
+  outline: 2px solid var(--dsw-alias-interactive-bg-hover-accent);
+  outline-offset: -1px;
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .gitRow { animation: none; }
+}
diff --git a/src/client/filetrace/ops.ts b/src/client/changes/ops.ts
similarity index 95%
rename from src/client/filetrace/ops.ts
rename to src/client/changes/ops.ts
index 522f60d..8eb9ca8 100644
--- a/src/client/filetrace/ops.ts
+++ b/src/client/changes/ops.ts
@@ -1,10 +1,10 @@
 /**
- * File-operation extraction for the file-trace tab: folds the session's
- * append-only event log (`tool/call` + `tool/result` pairs) into one op per
- * file-touching call — the same semantics as the standalone dsh-file-trace
- * plugin's Chat-view extraction, reading the authoritative event log instead
- * (the repo's stated preference for cross-feature session data). Pure — no
- * React, no DOM.
+ * File-operation extraction for the changes tab's session lens: folds the
+ * session's append-only event log (`tool/call` + `tool/result` pairs) into
+ * one op per file-touching call — the same semantics as the standalone
+ * dsh-file-trace plugin's Chat-view extraction, reading the authoritative
+ * event log instead (the repo's stated preference for cross-feature session
+ * data). Pure — no React, no DOM.
  */
 import type { SidebarSessionEvent } from '../../context-types.ts'
 
diff --git a/src/client/diff/DiffFiles.tsx b/src/client/diff/DiffFiles.tsx
new file mode 100644
index 0000000..ce03cbf
--- /dev/null
+++ b/src/client/diff/DiffFiles.tsx
@@ -0,0 +1,122 @@
+/**
+ * A full unified-diff document (one changed file, or every file of a commit
+ * patch): collapsible per-file headers — source files open by default, tests
+ * / docs / generated files stay folded — each expanded file rendering through
+ * the shared {@link DiffRows} (so git diffs get the same rewrite tinting,
+ * intra-line highlights, syntax colors and hunk folds as session-op diffs).
+ * Untracked files produce no `git diff` output; the caller passes their
+ * content to render as a full-file addition instead.
+ */
+import { useEffect, useMemo, useState, type ReactNode } from 'react'
+import clsx from 'clsx'
+import { t } from '../locales.ts'
+import { diffStats, displayPath, parseUnifiedDiff, unifiedSegments, untrackedFile, type DiffFile } from './rows.ts'
+import { langOfPath } from './highlight.ts'
+import { DiffRows } from './DiffRows.tsx'
+import css from './diff.module.css'
+
+const TEST_PATH = /(^|\/)(?:__tests__|tests?|specs?|fixtures?|mocks?|snapshots?)(?:\/|$)|\.(?:test|spec)\.[^/]+$/i
+const DOC_PATH = /(^|\/)(?:docs?|documentation)(?:\/|$)|(^|\/)(?:readme|changelog|contributing|license|authors|notice)(\.[^/]*)?$/i
+const GENERATED_PATH = /(^|\/)(?:dist|build|coverage|generated|vendor|node_modules)(?:\/|$)|(^|\/)(?:package-lock\.json|pnpm-lock\.yaml|yarn\.lock|bun\.lockb?|composer\.lock|cargo\.lock|poetry\.lock)$/i
+const SOURCE_PATH = /\.(?:js|jsx|mjs|cjs|ts|tsx|mts|cts|py|pyw|rb|php|java|kt|kts|scala|go|rs|swift|c|h|cc|cpp|cxx|hpp|hh|hxx|cs|fs|fsx|vb|dart|lua|r|ex|exs|erl|hrl|clj|cljs|cljc|groovy|sh|bash|zsh|fish|ps1|sql|vue|svelte|astro|html|htm|css|scss|sass|less)$/i
+
+/** Source files open by default; tests, docs, generated files and unknown types stay folded. */
+function defaultExpandedFiles(files: readonly DiffFile[]): Set<number> {
+  const expanded = new Set<number>()
+  files.forEach((file, index) => {
+    const path = displayPath(file.newPath === '/dev/null' ? file.oldPath : file.newPath)
+    if (!file.binary && file.hunks.length > 0
+      && !TEST_PATH.test(path) && !DOC_PATH.test(path) && !GENERATED_PATH.test(path)
+      && SOURCE_PATH.test(path)) {
+      expanded.add(index)
+    }
+  })
+  return expanded
+}
+
+/** The file header badge: added / deleted / renamed / binary ('' for a plain edit). */
+function fileTag(file: DiffFile): string | null {
+  if (file.binary) return t('diffBinary')
+  if (file.oldPath === '/dev/null') return t('diffAdded')
+  if (file.newPath === '/dev/null') return t('diffDeleted')
+  const oldPath = displayPath(file.oldPath)
+  const newPath = displayPath(file.newPath)
+  if (oldPath !== newPath) return t('diffRenamed')
+  return null
+}
+
+export interface DiffFilesProps {
+  /** Unified diff text (`git.diff` or `git.commit-diff` payloads). */
+  diff: string
+  /** Untracked-file content: when present, renders as a full-file addition instead of parsing. */
+  untrackedPath?: string
+  untrackedContent?: string
+}
+
+export function DiffFiles({ diff, untrackedPath, untrackedContent }: DiffFilesProps) {
+  const parsed = useMemo(() => {
+    if (untrackedPath !== undefined) {
+      return { files: [untrackedFile(untrackedPath, untrackedContent ?? '')] }
+    }
+    return parseUnifiedDiff(diff)
+  }, [diff, untrackedPath, untrackedContent])
+  const [expandedFiles, setExpandedFiles] = useState<Set<number>>(() => defaultExpandedFiles(parsed.files))
+  useEffect(() => { setExpandedFiles(defaultExpandedFiles(parsed.files)) }, [parsed])
+
+  // Segments and header stats computed once per file.
+  const files = useMemo(
+    () => parsed.files.map((file) => {
+      const segments = unifiedSegments(file)
+      return { file, segments, stats: diffStats(segments) }
+    }),
+    [parsed],
+  )
+
+  const renderFile = (entry: (typeof files)[number], fileIndex: number): ReactNode => {
+    const { file, segments, stats } = entry
+    const tag = fileTag(file)
+    const from = displayPath(file.oldPath)
+    const to = displayPath(file.newPath)
+    const expandable = !file.binary && file.hunks.length > 0
+    const fileExpanded = expandedFiles.has(fileIndex)
+    return (
+      <div key={`file-${String(fileIndex)}`} className={css.fileBlock}>
+        <button
+          type="button"
+          className={css.file}
+          disabled={!expandable}
+          aria-expanded={expandable ? fileExpanded : undefined}
+          onClick={() => {
+            setExpandedFiles(current => {
+              const next = new Set(current)
+              if (next.has(fileIndex)) next.delete(fileIndex)
+              else next.add(fileIndex)
+              return next
+            })
+          }}
+        >
+          {expandable && <span aria-hidden="true" className={clsx(css.fileChevron, fileExpanded && css.fileChevronExpanded)}>›</span>}
+          <span className={css.filePath}>{to}</span>
+          {from !== to && <span className={css.fileOld}>← {from}</span>}
+          {tag !== null && <span className={css.fileTag}>{tag}</span>}
+          {expandable && (stats.added > 0 || stats.deleted > 0) && (
+            <span className={css.fileStats}>
+              {stats.added > 0 && <span className={css.statAdd}>+{String(stats.added)}</span>}
+              {stats.deleted > 0 && <span className={css.statDel}>−{String(stats.deleted)}</span>}
+            </span>
+          )}
+        </button>
+        {expandable && fileExpanded && (
+          <DiffRows segments={segments} lang={langOfPath(to)} />
+        )}
+      </div>
+    )
+  }
+
+  if (parsed.files.length === 0) return null
+  return (
+    <div className={css.files}>
+      {files.map(renderFile)}
+    </div>
+  )
+}
diff --git a/src/client/diff/DiffRows.tsx b/src/client/diff/DiffRows.tsx
new file mode 100644
index 0000000..8316546
--- /dev/null
+++ b/src/client/diff/DiffRows.tsx
@@ -0,0 +1,270 @@
+/**
+ * The one diff renderer every file-change surface shares (the changes tab's
+ * inline preview pane and the diff tab): fold-capable hunk rows with old/new
+ * line gutters, rewrite (mod) tinting with intra-line character highlights,
+ * lightweight syntax coloring, and long-line folding. Presentational — the
+ * segments arrive precomputed (session ops via buildDiffSegments, git diffs
+ * via unifiedSegments) so both producers render identically.
+ */
+import { useEffect, useMemo, useState, type ReactElement, type ReactNode } from 'react'
+import { t } from '../locales.ts'
+import { coalesceInline, diffInline, MIN_FOLD, type DiffRow, type DiffSegment, type InlineDiff } from './rows.ts'
+import { hasBlockComment, isColored, scanLine, type CodeToken, type TokenType } from './highlight.ts'
+import css from './diff.module.css'
+
+/** Long diff lines fold to one ellipsized row; the threshold is the char count. */
+const FOLD_THRESHOLD = 120
+
+/** Rendered hunk rows per file capped at this count; expand reveals the rest. */
+const MAX_ROWS = 600
+
+/** Token class -> CSS color class ('' inherits the row's diff color). */
+const TOKEN_CLASS: Readonly<Record<TokenType, string>> = {
+  plain: '',
+  comment: css.tokComment ?? '',
+  string: css.tokString ?? '',
+  keyword: css.tokKeyword ?? '',
+  number: css.tokNumber ?? '',
+  type: css.tokType ?? '',
+  function: css.tokFunction ?? '',
+  macro: css.tokMacro ?? '',
+}
+
+/** One token span's class list: its color class, plus the change tint. */
+function tokenSpanClass(type: TokenType, changed: boolean): string {
+  const color = TOKEN_CLASS[type]
+  return changed ? `${color} ${css.inlineChange}` : color
+}
+
+/** Render scanned tokens as colored nodes; uncolored runs stay text. */
+function tokensToNodes(tokens: readonly CodeToken[], changed = false): ReactNode[] {
+  const nodes: ReactNode[] = []
+  for (const token of tokens) {
+    if (!changed && !isColored(token)) nodes.push(token.text)
+    else nodes.push(<span key={String(nodes.length)} className={tokenSpanClass(token.type, changed)}>{token.text}</span>)
+  }
+  return nodes
+}
+
+/**
+ * Intra-line diffs for mod-row pairs, keyed by row identity: each mod-run's
+ * first half (old side) pairs with its second half (new side), each pair
+ * diffed by common prefix/suffix so both sides highlight the exact changed
+ * substring.
+ */
+function buildInlineMap(segments: readonly DiffSegment[]): Map<DiffRow, InlineDiff> {
+  const map = new Map<DiffRow, InlineDiff>()
+  for (const segment of segments) {
+    if (segment.kind !== 'hunk') continue
+    const rows = segment.rows
+    let i = 0
+    while (i < rows.length) {
+      if (rows[i]!.kind !== 'mod') { i += 1; continue }
+      let j = i
+      while (j < rows.length && rows[j]!.kind === 'mod') j += 1
+      const block = rows.slice(i, j)
+      const half = Math.floor(block.length / 2)
+      for (let p = 0; p < half; p += 1) {
+        const delRow = block[p]!
+        const addRow = block[p + half]!
+        const inline = diffInline(delRow.text, addRow.text)
+        map.set(delRow, inline)
+        map.set(addRow, inline)
+      }
+      i = j
+    }
+  }
+  return map
+}
+
+/**
+ * Per-row block-comment entry state for a diff: the old side threads along
+ * old-line order and the new side along new-line order (the row order
+ * preserves both), so multi-line comments color correctly on each side.
+ */
+function diffBlockEntries(segments: readonly DiffSegment[], lang: string | undefined): Map<DiffRow, boolean> {
+  const entries = new Map<DiffRow, boolean>()
+  if (!hasBlockComment(lang)) return entries
+  let oldIn = false
+  let newIn = false
+  for (const segment of segments) {
+    if (segment.kind !== 'hunk') continue
+    for (const row of segment.rows) {
+      const isOld = row.oldLine !== undefined
+      const isNew = row.newLine !== undefined
+      entries.set(row, isOld ? oldIn : newIn)
+      if (isOld) oldIn = scanLine(row.text, lang, oldIn).inBlock
+      if (isNew) newIn = scanLine(row.text, lang, newIn).inBlock
+    }
+  }
+  return entries
+}
+
+export interface DiffRowsProps {
+  /** Precomputed segments (hunks and folds) for one file's diff. */
+  segments: readonly DiffSegment[]
+  /** Syntax language id (langOfPath); undefined renders plain text. */
+  lang?: string
+}
+
+/** One file's diff rows: fold chips between hunks, highlighted code rows. */
+export function DiffRows({ segments, lang }: DiffRowsProps) {
+  // Long diff lines fold to one ellipsized row; the set holds expanded row keys.
+  const [expandedLines, setExpandedLines] = useState<ReadonlySet<string>>(new Set())
+  // Hunk-fold segments expanded by index; default collapsed.
+  const [expandedFolds, setExpandedFolds] = useState<ReadonlySet<number>>(new Set())
+  // Row-count cap expanded: a huge file renders head rows plus this button.
+  const [expandedAll, setExpandedAll] = useState(false)
+  // Reset all folding when the segments identity changes (new target).
+  useEffect(() => {
+    setExpandedLines(new Set())
+    setExpandedFolds(new Set())
+    setExpandedAll(false)
+  }, [segments])
+
+  const inlineMap = useMemo(() => buildInlineMap(segments), [segments])
+  const blockEntries = useMemo(() => diffBlockEntries(segments, lang), [segments, lang])
+
+  /** One diff row: colored sign + syntax-colored text, long-line fold toggle. */
+  const renderDiffRow = (row: DiffRow, rowKey: string): ReactElement => {
+    if (row.kind === 'meta') {
+      return (
+        <div key={rowKey} className={css.row} data-kind="meta">
+          <span className={css.metaText}>{row.text}</span>
+        </div>
+      )
+    }
+    const isLong = row.text.length > FOLD_THRESHOLD
+    const isFolded = isLong && !expandedLines.has(rowKey)
+    const blockEntry = blockEntries.get(row) ?? false
+    return (
+      <div
+        key={rowKey}
+        className={css.row}
+        data-kind={row.kind}
+        data-folded={isFolded ? 'true' : undefined}
+        onClick={isLong ? () => {
+          setExpandedLines(prev => {
+            const next = new Set(prev)
+            if (next.has(rowKey)) next.delete(rowKey)
+            else next.add(rowKey)
+            return next
+          })
+        } : undefined}
+        title={isFolded ? row.text : undefined}
+      >
+        <span className={css.lineNo}>{row.oldLine !== undefined ? String(row.oldLine) : ''}</span>
+        <span className={css.lineNo}>{row.newLine !== undefined ? String(row.newLine) : ''}</span>
+        <span className={css.sign}>{row.kind === 'del' ? '-' : row.kind === 'add' ? '+' : row.kind === 'mod' ? '~' : ' '}</span>
+        <span className={css.text} data-folded={isFolded ? 'true' : undefined}>
+          {row.kind === 'mod' && (() => {
+            const inline = inlineMap.get(row)
+            if (inline === undefined) return tokensToNodes(scanLine(row.text, lang, blockEntry).tokens)
+            // Coalesced change runs, each split into syntax tokens with
+            // block-comment state threaded across the runs of this line.
+            const side = coalesceInline(row.oldLine !== undefined ? inline.old : inline.next)
+            const nodes: ReactNode[] = []
+            let state = blockEntry
+            for (const seg of side) {
+              const scan = scanLine(seg.text, lang, state)
+              state = scan.inBlock
+              nodes.push(...tokensToNodes(scan.tokens, seg.changed))
+            }
+            return nodes
+          })()}
+          {row.kind !== 'mod' && tokensToNodes(scanLine(row.text, lang, blockEntry).tokens)}
+        </span>
+      </div>
+    )
+  }
+
+  let renderedRows = 0
+  const renderSegment = (segment: DiffSegment, segIndex: number): ReactNode => {
+    if (segment.kind === 'hunk') {
+      const capped = !expandedAll && renderedRows + segment.rows.length > MAX_ROWS
+      const rows = capped ? segment.rows.slice(0, Math.max(MAX_ROWS - renderedRows, 0)) : segment.rows
+      renderedRows += rows.length
+      return (
+        <div key={`hunk-${String(segIndex)}`}>
+          {rows.map((row, index) => renderDiffRow(row, `${segIndex}-${String(index)}`))}
+        </div>
+      )
+    }
+    const expandable = segment.rows !== undefined && segment.count >= MIN_FOLD
+    if (!expandable) {
+      // A tiny fold (or a git gap with no rows to reveal): a quiet marker.
+      return (
+        <div key={`fold-${String(segIndex)}`} className={css.foldRow}>
+          <span className={css.foldMarker} title={t('changesContext')}>
+            {t('changesFold', { count: segment.count })}
+          </span>
+        </div>
+      )
+    }
+    const isExpanded = expandedFolds.has(segIndex)
+    return (
+      <div
+        key={`fold-${String(segIndex)}`}
+        className={css.foldRow}
+        data-expanded={isExpanded ? 'true' : undefined}
+        onClick={() => {
+          setExpandedFolds(prev => {
+            const next = new Set(prev)
+            if (next.has(segIndex)) next.delete(segIndex)
+            else next.add(segIndex)
+            return next
+          })
+        }}
+      >
+        {isExpanded
+          ? segment.rows!.map((row, index) => renderDiffRow(row, `${segIndex}-${String(index)}`))
+          : (
+            <span className={css.foldMarker} title={t('changesContext')}>
+              {t('changesFold', { count: segment.count })}
+            </span>
+          )}
+      </div>
+    )
+  }
+
+  const parts = segments.map(renderSegment)
+  return (
+    <div className={css.rows}>
+      {parts}
+      {renderedRows >= MAX_ROWS && !expandedAll && (
+        <button type="button" className={css.expand} onClick={() => { setExpandedAll(true) }}>
+          {t('diffExpand', { count: segments.reduce((sum, s) => sum + (s.kind === 'hunk' ? s.rows.length : 0), 0) - renderedRows })}
+        </button>
+      )}
+    </div>
+  )
+}
+
+export interface ReadRowsProps {
+  /** The file lines with their real line numbers (parseReadLines output). */
+  lines: ReadonlyArray<{ line: number; text: string }>
+  /** Syntax language id (langOfPath); undefined renders plain text. */
+  lang?: string
+}
+
+/** The read view: a line-numbered, syntax-colored slice of a read file. */
+export function ReadRows({ lines, lang }: ReadRowsProps) {
+  const rows = useMemo(() => {
+    let state = false
+    return lines.map((line) => {
+      const scan = scanLine(line.text, lang, state)
+      state = scan.inBlock
+      return { line: line.line, nodes: tokensToNodes(scan.tokens) }
+    })
+  }, [lines, lang])
+  return (
+    <div className={css.rows}>
+      {rows.map((row) => (
+        <div key={String(row.line)} className={css.row} data-kind="read">
+          <span className={css.lineNo}>{String(row.line)}</span>
+          <span className={css.text}>{row.nodes}</span>
+        </div>
+      ))}
+    </div>
+  )
+}
diff --git a/src/client/diff/diff.module.css b/src/client/diff/diff.module.css
new file mode 100644
index 0000000..bdb59c8
--- /dev/null
+++ b/src/client/diff/diff.module.css
@@ -0,0 +1,81 @@
+/* The shared diff renderer (DiffRows / DiffFiles): one visual language for
+   every file-change surface — the changes tab's preview pane, the diff tab,
+   session-op diffs and git diffs alike. Semantic --dsw-alias tokens only
+   (skin contract); the syntax-token hues derive from the alias state tokens
+   via color-mix so they sit BETWEEN the diff colors (violet keywords, teal
+   strings, brand-tinted types, warn-family numbers/functions, magenta
+   macros) instead of colliding with red del / green add / blue mod. */
+
+.rows { padding: 4px 0 8px; font-family: var(--ds-font-family-code, monospace); font-size: 11px; }
+.row { display: flex; align-items: flex-start; gap: 5px; padding: 0 10px; line-height: 18px; cursor: default; }
+.row[data-folded='true'] { cursor: pointer; }
+.lineNo { flex: none; width: 2.5em; color: var(--dsw-alias-label-tertiary); text-align: right; user-select: none; font-size: 10px; }
+.sign { flex: none; width: 1em; text-align: center; user-select: none; font-weight: 700; }
+
+.row[data-kind='del'] .sign, .row[data-kind='del'] .text { color: var(--dsw-alias-state-error-primary); }
+.row[data-kind='add'] .sign, .row[data-kind='add'] .text { color: var(--dsw-alias-state-success-primary); }
+.row[data-kind='mod'] .sign, .row[data-kind='mod'] .text { color: var(--dsw-alias-state-business-primary); }
+.row[data-kind='context'] .sign, .row[data-kind='context'] .text { color: var(--dsw-alias-label-secondary); }
+.row[data-kind='read'] .text { color: var(--dsw-alias-label-primary); }
+
+/* Faint row tints under changed lines (GitHub-style, lighter than the text
+   hue so the syntax colors stay readable on top). */
+.row[data-kind='del'] { background: color-mix(in srgb, var(--dsw-alias-state-error-primary) 8%, transparent); }
+.row[data-kind='add'] { background: color-mix(in srgb, var(--dsw-alias-state-success-primary) 8%, transparent); }
+.row[data-kind='mod'] { background: color-mix(in srgb, var(--dsw-alias-state-business-primary) 8%, transparent); }
+
+.row .text { flex: 1; min-width: 0; white-space: pre-wrap; word-break: break-word; }
+.row[data-folded='true'] .text { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
+
+/* The `\ No newline at end of file` marker row attached to a hunk's tail. */
+.row[data-kind='meta'] .metaText { color: var(--dsw-alias-label-tertiary); font-style: italic; }
+
+/* Intra-line changed substring inside a rewritten (mod) line. */
+.inlineChange { background: color-mix(in srgb, var(--dsw-alias-state-business-primary) 26%, transparent); border-radius: 3px; padding: 0 1px; }
+
+/* Syntax-token colors: alias-token mixes between the diff hues. */
+.tokComment { color: var(--dsw-alias-label-tertiary); font-style: italic; }
+.tokKeyword { color: color-mix(in oklab, var(--dsw-alias-state-business-primary) 55%, var(--dsw-alias-state-error-primary)); }
+.tokString { color: color-mix(in oklab, var(--dsw-alias-state-success-primary) 45%, var(--dsw-alias-state-business-primary)); }
+.tokType { color: color-mix(in oklab, var(--dsw-alias-brand-primary) 60%, var(--dsw-alias-state-success-primary)); }
+.tokNumber { color: var(--dsw-alias-state-warn-primary); }
+.tokFunction { color: color-mix(in oklab, var(--dsw-alias-state-warn-primary) 55%, var(--dsw-alias-state-error-primary)); }
+.tokMacro { color: color-mix(in oklab, var(--dsw-alias-state-error-primary) 45%, var(--dsw-alias-state-business-primary)); }
+
+/* Hunk-fold row: collapsed marker chip; expanded padding drops to 0 so the
+   revealed rows keep the x-alignment of hunk rows (they carry their own). */
+.foldRow { padding: 0 10px; cursor: pointer; }
+.foldRow[data-expanded='true'] { padding: 0; }
+.foldRow:hover { background: var(--dsw-alias-interactive-bg-hover); }
+.foldMarker { display: inline-block; padding: 2px 6px; border-radius: 4px; margin: 2px 0; color: var(--dsw-alias-label-tertiary); background: var(--dsw-alias-interactive-bg-hover); font-style: italic; }
+.foldRow[data-expanded='true'] { cursor: default; }
+.foldRow[data-expanded='true'] .foldMarker { display: none; }
+
+/* The huge-file overflow reveal under a capped hunk. */
+.expand { display: block; width: calc(100% - 20px); margin: 4px 10px; padding: 4px; border: 1px solid var(--dsw-alias-border-l1); border-radius: 6px; background: transparent; color: var(--dsw-alias-label-secondary); font: inherit; font-size: 11px; cursor: pointer; }
+.expand:hover { background: var(--dsw-alias-interactive-bg-hover); color: var(--dsw-alias-label-primary); }
+
+/* Multi-file documents (commit patches): collapsible file headers. */
+.files { display: flex; flex-direction: column; }
+.fileBlock { display: flex; flex-direction: column; }
+.file { display: flex; align-items: center; gap: 6px; width: 100%; padding: 6px 10px; border: 0; background: transparent; font: inherit; font-size: 11px; text-align: left; cursor: pointer; }
+.file:disabled { cursor: default; }
+.file:hover:not(:disabled) { background: var(--dsw-alias-interactive-bg-hover); }
+.fileChevron { flex: none; width: 12px; color: var(--dsw-alias-label-tertiary); transition: transform var(--ds-transition-duration-slow) var(--ds-ease-in-out); }
+.fileChevronExpanded { transform: rotate(90deg); }
+.filePath { font-family: var(--ds-font-family-code, monospace); color: var(--dsw-alias-label-primary); word-break: break-all; min-width: 0; }
+.fileOld { flex: none; max-width: 40%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: var(--dsw-alias-label-tertiary); font-family: var(--ds-font-family-code, monospace); }
+.fileTag { flex: none; border-radius: 4px; font-size: 10px; line-height: 16px; padding: 0 5px; background: var(--dsw-alias-interactive-bg-hover); color: var(--dsw-alias-label-secondary); }
+.fileStats { margin-left: auto; flex: none; display: inline-flex; gap: 5px; font-size: 10px; font-family: var(--ds-font-family-code, monospace); }
+.statAdd { color: var(--dsw-alias-state-success-primary); }
+.statDel { color: var(--dsw-alias-state-error-primary); }
+
+/* Keyboard focus rings match the shared sidebar convention. */
+.row:focus-visible, .foldRow:focus-visible, .file:focus-visible, .expand:focus-visible {
+  outline: 2px solid var(--dsw-alias-interactive-bg-hover-accent);
+  outline-offset: -1px;
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .fileChevron { transition: none; }
+}
diff --git a/src/client/filetrace/highlight.ts b/src/client/diff/highlight.ts
similarity index 96%
rename from src/client/filetrace/highlight.ts
rename to src/client/diff/highlight.ts
index e9468e9..7981a99 100644
--- a/src/client/filetrace/highlight.ts
+++ b/src/client/diff/highlight.ts
@@ -1,11 +1,12 @@
 /**
- * Lightweight syntax highlighting for the file-trace panel: extension-based
- * language detection plus a single-pass line tokenizer that colors comments,
- * strings, numbers, keywords, types, functions, and preprocessor directives
- * for common languages (C/C++, Java, C#, JS/TS, Python, Go, Rust, shell, batch,
- * PowerShell, and config formats). Pure functions only — no React, no DOM.
- * Multi-line block-comment state threads across lines via scanLine's
- * inBlock parameter, so interior lines of a block comment color correctly.
+ * Lightweight syntax highlighting for the shared diff renderer: extension-
+ * based language detection plus a single-pass line tokenizer that colors
+ * comments, strings, numbers, keywords, types, functions, and preprocessor
+ * directives for common languages (C/C++, Java, C#, JS/TS, Python, Go, Rust,
+ * shell, batch, PowerShell, and config formats). Pure functions only — no
+ * React, no DOM. Multi-line block-comment state threads across lines via
+ * scanLine's inBlock parameter, so interior lines of a block comment color
+ * correctly.
  */
 
 /** Token classes mapped 1:1 to panel CSS color classes. */
diff --git a/src/client/diff/rows.ts b/src/client/diff/rows.ts
new file mode 100644
index 0000000..bfd7e68
--- /dev/null
+++ b/src/client/diff/rows.ts
@@ -0,0 +1,473 @@
+/**
+ * The one diff engine every file-change surface shares (the changes tab's
+ * git and session lenses, the diff tab): a unified DiffRow model fed by two
+ * producers — a line LCS over known contents (session file ops) and git's
+ * own unified-diff text (worktree/commit diffs, via `parseUnifiedDiff` +
+ * `unifiedSegments`) — collapsed into hunk/fold segments for the shared
+ * renderer. Pure functions only — no React, no DOM.
+ */
+
+/** One rendered diff row. */
+export interface DiffRow {
+  /** Change class: 'context' shared, 'del' removed, 'add' added, 'mod'
+   *  rewritten (paired del+add), 'meta' an attached marker row. */
+  readonly kind: 'context' | 'del' | 'add' | 'mod' | 'meta'
+  /** Old-side 1-based line number; absent on pure additions. */
+  readonly oldLine?: number
+  /** New-side 1-based line number; absent on pure deletions. */
+  readonly newLine?: number
+  /** The line's text without its terminator. */
+  readonly text: string
+}
+
+/**
+ * Longest-common-subsequence table over line equality.
+ * @param oldLines - old side lines.
+ * @param newLines - new side lines.
+ * @returns the LCS length matrix (rows index oldLines, columns newLines).
+ */
+function lcsTable(oldLines: readonly string[], newLines: readonly string[]): number[][] {
+  const table: number[][] = Array.from({ length: oldLines.length + 1 }, () => new Array<number>(newLines.length + 1).fill(0))
+  for (let i = oldLines.length - 1; i >= 0; i -= 1) {
+    for (let j = newLines.length - 1; j >= 0; j -= 1) {
+      table[i]![j] = oldLines[i] === newLines[j]
+        ? table[i + 1]![j + 1]! + 1
+        : Math.max(table[i + 1]![j]!, table[i]![j + 1]!)
+    }
+  }
+  return table
+}
+
+/**
+ * Pair each del-run with the add-run that follows it: the overlapping
+ * `min(len)` rows on both sides become 'mod' so rewrites tint distinctly and
+ * receive intra-line highlighting. Pure — returns a new array when anything
+ * changed. Shared by the LCS walk and the unified-diff converter so git
+ * hunks rewrite-pair exactly like session ops do.
+ */
+export function pairMods(rows: readonly DiffRow[]): DiffRow[] {
+  const out = rows.slice()
+  let k = 0
+  while (k < out.length) {
+    if (out[k]!.kind !== 'del') { k += 1; continue }
+    const delStart = k
+    while (k < out.length && out[k]!.kind === 'del') k += 1
+    const addStart = k
+    while (k < out.length && out[k]!.kind === 'add') k += 1
+    const pairs = Math.min(addStart - delStart, k - addStart)
+    for (let p = 0; p < pairs; p += 1) {
+      out[delStart + p] = { ...out[delStart + p]!, kind: 'mod' }
+      out[addStart + p] = { ...out[addStart + p]!, kind: 'mod' }
+    }
+  }
+  return out
+}
+
+/**
+ * Line diff by LCS walk with rewrite pairing: the raw walk emits context/del/
+ * add rows; `pairMods` marks rewritten pairs as 'mod'.
+ * @param oldText - the previous content; empty string diffs against nothing.
+ * @param newText - the next content.
+ * @returns ordered diff rows, old-side deletions before new-side additions.
+ */
+export function diffLines(oldText: string, newText: string): DiffRow[] {
+  const oldLines = oldText.length === 0 ? [] : oldText.split('\n')
+  const newLines = newText.length === 0 ? [] : newText.split('\n')
+  const table = lcsTable(oldLines, newLines)
+  const raw: DiffRow[] = []
+  let i = 0
+  let j = 0
+  while (i < oldLines.length && j < newLines.length) {
+    if (oldLines[i] === newLines[j]) {
+      raw.push({ kind: 'context', oldLine: i + 1, newLine: j + 1, text: oldLines[i]! })
+      i += 1
+      j += 1
+    } else if (table[i + 1]![j]! >= table[i]![j + 1]!) {
+      raw.push({ kind: 'del', oldLine: i + 1, text: oldLines[i]! })
+      i += 1
+    } else {
+      raw.push({ kind: 'add', newLine: j + 1, text: newLines[j]! })
+      j += 1
+    }
+  }
+  while (i < oldLines.length) {
+    raw.push({ kind: 'del', oldLine: i + 1, text: oldLines[i]! })
+    i += 1
+  }
+  while (j < newLines.length) {
+    raw.push({ kind: 'add', newLine: j + 1, text: newLines[j]! })
+    j += 1
+  }
+  return pairMods(raw)
+}
+
+/** One rendered hunk: change rows plus the surrounding context window. */
+export interface HunkSegment { readonly kind: 'hunk'; readonly rows: readonly DiffRow[] }
+
+/** One collapsed run of unchanged rows (the "… n 行" fold). */
+export interface FoldSegment {
+  readonly kind: 'fold'
+  /** The rows this fold hides, when the producer knows them (session diffs
+   *  re-derive them from full contents; git gaps never emitted the text, so
+   *  those folds carry only their line ranges and cannot expand). */
+  readonly rows?: readonly DiffRow[]
+  /** How many rows the fold hides. */
+  readonly count: number
+  readonly oldStart: number
+  readonly oldEnd: number
+  readonly newStart: number
+  readonly newEnd: number
+}
+
+export type DiffSegment = HunkSegment | FoldSegment
+
+/** Context window (rows around a change) kept visible in a hunk. */
+export const HUNK_CONTEXT = 3
+
+/** Folded context runs shorter than this are shown directly, not collapsed. */
+export const MIN_FOLD = 3
+
+/**
+ * Group a line diff into hunks and folded context runs. Consecutive changes
+ * whose gap fits within the context window merge into one hunk; unchanged
+ * regions between hunks (and any surrounding the whole diff) become fold
+ * segments that default collapsed. This yields the file-hunk presentation
+ * familiar from terminal diffs (Claude Code / git hunk headers).
+ * @param rows - the flat diff rows.
+ * @param context - how many unchanged rows around a change stay visible.
+ * @returns ordered segments (hunks and folds).
+ */
+export function buildDiffSegments(rows: readonly DiffRow[], context = HUNK_CONTEXT): DiffSegment[] {
+  if (rows.length === 0) return []
+  const changeIndexes = rows.flatMap((row, index) => (row.kind === 'context' || row.kind === 'meta' ? [] : [index]))
+  if (changeIndexes.length === 0) {
+    // Whole diff is unchanged (or a pure no-op): hide it all behind one fold.
+    return [{
+      kind: 'fold', rows: [...rows], count: rows.length,
+      oldStart: 1, oldEnd: rows.length, newStart: 1, newEnd: rows.length,
+    }]
+  }
+  // Cluster changes into runs whose gaps fit within 2*context+1 rows.
+  const hunks: { start: number; end: number }[] = []
+  for (const ci of changeIndexes) {
+    const start = Math.max(0, ci - context)
+    const end = Math.min(rows.length - 1, ci + context)
+    const last = hunks[hunks.length - 1]
+    if (last !== undefined && start <= last.end + 1) {
+      last.end = Math.max(last.end, end)
+    } else {
+      hunks.push({ start, end })
+    }
+  }
+  const segments: DiffSegment[] = []
+  let cursor = 0
+  for (const hunk of hunks) {
+    if (hunk.start > cursor) segments.push(foldOf(rows.slice(cursor, hunk.start)))
+    segments.push({ kind: 'hunk', rows: rows.slice(hunk.start, hunk.end + 1) })
+    cursor = hunk.end + 1
+  }
+  if (cursor < rows.length) segments.push(foldOf(rows.slice(cursor)))
+  return segments
+}
+
+function foldOf(rows: readonly DiffRow[]): FoldSegment {
+  return {
+    kind: 'fold',
+    rows,
+    count: rows.length,
+    oldStart: firstOldLine(rows) ?? 1,
+    oldEnd: lastOldLine(rows) ?? 0,
+    newStart: firstNewLine(rows) ?? 1,
+    newEnd: lastNewLine(rows) ?? 0,
+  }
+}
+
+function firstOldLine(rows: readonly DiffRow[]): number | undefined {
+  for (const row of rows) if (row.oldLine !== undefined) return row.oldLine
+  return undefined
+}
+function lastOldLine(rows: readonly DiffRow[]): number | undefined {
+  for (let i = rows.length - 1; i >= 0; i -= 1) if (rows[i]!.oldLine !== undefined) return rows[i]!.oldLine
+  return undefined
+}
+function firstNewLine(rows: readonly DiffRow[]): number | undefined {
+  for (const row of rows) if (row.newLine !== undefined) return row.newLine
+  return undefined
+}
+function lastNewLine(rows: readonly DiffRow[]): number | undefined {
+  for (let i = rows.length - 1; i >= 0; i -= 1) if (rows[i]!.newLine !== undefined) return rows[i]!.newLine
+  return undefined
+}
+
+/** One intra-line segment: a run of chars with a changed flag. */
+export interface InlineSegment { readonly text: string; readonly changed: boolean }
+/** Each side's intra-line segments. */
+export interface InlineDiff { readonly old: readonly InlineSegment[]; readonly next: readonly InlineSegment[] }
+
+/**
+ * Intra-line diff by common prefix/suffix: the shared leading and trailing
+ * characters stay unchanged, and only the differing middle is marked changed
+ * on both sides. This never highlights identical characters and keeps a small
+ * edit inside a long line immediately visible. Pure, no React/DOM.
+ * @param oldText - the old line.
+ * @param newText - the new line.
+ * @returns per-side segments marking changed runs.
+ */
+export function diffInline(oldText: string, newText: string): InlineDiff {
+  const minLen = Math.min(oldText.length, newText.length)
+  let prefix = 0
+  while (prefix < minLen && oldText[prefix] === newText[prefix]) prefix += 1
+  let suffix = 0
+  while (suffix < minLen - prefix && oldText[oldText.length - 1 - suffix] === newText[newText.length - 1 - suffix]) suffix += 1
+  const oldMidStart = prefix
+  const oldMidEnd = oldText.length - suffix
+  const newMidStart = prefix
+  const newMidEnd = newText.length - suffix
+  const segments = (text: string, midStart: number, midEnd: number): InlineSegment[] => {
+    const out: InlineSegment[] = []
+    if (midStart > 0) out.push({ text: text.slice(0, midStart), changed: false })
+    const mid = text.slice(midStart, midEnd)
+    if (mid.length > 0) out.push({ text: mid, changed: true })
+    if (midEnd < text.length) out.push({ text: text.slice(midEnd), changed: false })
+    return out
+  }
+  return { old: segments(oldText, oldMidStart, oldMidEnd), next: segments(newText, newMidStart, newMidEnd) }
+}
+
+/**
+ * Merge adjacent inline segments sharing the same changed flag, so rendering
+ * wraps each run — not each character — in one span.
+ * @param segments - the raw per-character-heavy inline segments.
+ * @returns coalesced segments; identical text joined into runs.
+ */
+export function coalesceInline(segments: readonly InlineSegment[]): InlineSegment[] {
+  const out: InlineSegment[] = []
+  for (const seg of segments) {
+    const last = out[out.length - 1]
+    if (last !== undefined && last.changed === seg.changed) out[out.length - 1] = { text: last.text + seg.text, changed: seg.changed }
+    else out.push(seg)
+  }
+  return out
+}
+
+/** Human byte count for the panel meta row. */
+export function formatBytes(bytes: number): string {
+  if (bytes < 1024) return `${String(bytes)} B`
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`
+  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`
+}
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Unified-diff text (git) → DiffRow segments
+// ─────────────────────────────────────────────────────────────────────────────
+
+/** One parsed diff line of a unified diff (git's own hunk structure). */
+export interface DiffLine {
+  kind: 'ctx' | 'del' | 'add' | 'meta'
+  /** The line content without its diff marker ('' for the no-newline marker). */
+  text: string
+  /** Old-side line number (null for pure additions / metadata). */
+  oldNum: number | null
+  /** New-side line number (null for pure deletions / metadata). */
+  newNum: number | null
+}
+
+/** One parsed hunk. */
+export interface DiffHunk {
+  /** The old-side start line (`-a[,b]`). */
+  oldStart: number
+  /** The new-side start line (`+c[,d]`). */
+  newStart: number
+  /** The section text after the trailing `@@` (may be empty). */
+  header: string
+  lines: DiffLine[]
+}
+
+/** One parsed file section of a unified diff. */
+export interface DiffFile {
+  /** The `---` path verbatim ('/dev/null' for a new file). */
+  oldPath: string
+  /** The `+++` path verbatim ('/dev/null' for a deleted file). */
+  newPath: string
+  /** The file changed with binary content: no hunks to draw. */
+  binary: boolean
+  hunks: DiffHunk[]
+}
+
+/** The parsed unified diff. */
+export interface ParsedDiff {
+  files: DiffFile[]
+}
+
+/** Parse the hunk header `@@ -a[,b] +c[,d] @@ section` (section may contain '@@'). */
+function parseHunkHeader(line: string): { oldStart: number; newStart: number; header: string } | null {
+  const match = /^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@(.*)$/.exec(line)
+  if (match === null) return null
+  return { oldStart: Number(match[1]), newStart: Number(match[3]), header: match[5] ?? '' }
+}
+
+/**
+ * Parse `git diff --no-color` output into file sections and hunks. Rows
+ * outside a file section (leading noise) and metadata rows between the
+ * `diff --git`/`---`/`+++` headers and the first hunk (index lines, mode
+ * changes, rename/similarity lines) are skipped; a section that never
+ * reaches a hunk (a mode/rename-only change) stays hunkless so the caller
+ * can still draw its path.
+ */
+export function parseUnifiedDiff(text: string): ParsedDiff {
+  const files: DiffFile[] = []
+  let current: DiffFile | null = null
+  let inHunk = false
+  let hunk: DiffHunk | null = null
+  let oldNum = 0
+  let newNum = 0
+  const flushHunk = (): void => {
+    if (current !== null && hunk !== null) current.hunks.push(hunk)
+    hunk = null
+    inHunk = false
+  }
+  for (const raw of text.split('\n')) {
+    if (raw.startsWith('diff --git ')) {
+      flushHunk()
+      current = { oldPath: '', newPath: '', binary: false, hunks: [] }
+      files.push(current)
+      continue
+    }
+    if (current === null) continue
+    if (raw.startsWith('Binary files ') || raw === 'GIT binary patch') {
+      flushHunk()
+      current.binary = true
+      continue
+    }
+    if (raw.startsWith('--- ')) {
+      flushHunk()
+      current.oldPath = raw.slice(4)
+      continue
+    }
+    if (raw.startsWith('+++ ')) {
+      current.newPath = raw.slice(4)
+      continue
+    }
+    const header = parseHunkHeader(raw)
+    if (header !== null) {
+      flushHunk()
+      hunk = { oldStart: header.oldStart, newStart: header.newStart, header: header.header, lines: [] }
+      oldNum = header.oldStart
+      newNum = header.newStart
+      inHunk = true
+      continue
+    }
+    if (!inHunk || hunk === null) continue
+    const marker = raw[0]
+    if (marker === '\\') {
+      // `\ No newline at end of file`: metadata attached to the previous row.
+      hunk.lines.push({ kind: 'meta', text: raw.slice(1), oldNum: null, newNum: null })
+      continue
+    }
+    if (marker === ' ') {
+      hunk.lines.push({ kind: 'ctx', text: raw.slice(1), oldNum, newNum })
+      oldNum += 1
+      newNum += 1
+    } else if (marker === '-') {
+      hunk.lines.push({ kind: 'del', text: raw.slice(1), oldNum, newNum: null })
+      oldNum += 1
+    } else if (marker === '+') {
+      hunk.lines.push({ kind: 'add', text: raw.slice(1), oldNum: null, newNum })
+      newNum += 1
+    } else {
+      // Not a diff line (a hunk can never contain one): stop the hunk.
+      flushHunk()
+    }
+  }
+  flushHunk()
+  return { files }
+}
+
+/** One DiffLine row mapped onto the shared DiffRow model. */
+function rowOfLine(line: DiffLine): DiffRow {
+  if (line.kind === 'meta') return { kind: 'meta', text: line.text }
+  const kind: DiffRow['kind'] = line.kind === 'ctx' ? 'context' : line.kind
+  if (line.kind === 'del') return { kind, oldLine: line.oldNum ?? undefined, text: line.text }
+  if (line.kind === 'add') return { kind, newLine: line.newNum ?? undefined, text: line.text }
+  return { kind, oldLine: line.oldNum ?? undefined, newLine: line.newNum ?? undefined, text: line.text }
+}
+
+/**
+ * Convert one parsed unified-diff file into renderer segments: each hunk's
+ * lines become a paired-mod hunk segment, and the unemitted context gaps
+ * between hunks (git already trimmed them) become non-expandable folds that
+ * still carry their old/new line ranges. The rewrite pairing applies within
+ * each hunk, exactly like session-op diffs.
+ */
+export function unifiedSegments(file: DiffFile): DiffSegment[] {
+  const segments: DiffSegment[] = []
+  file.hunks.forEach((hunk, index) => {
+    const rows = pairMods(hunk.lines.map(rowOfLine))
+    const prev = file.hunks[index - 1]
+    if (prev !== undefined) {
+      // The gap git never emitted: rows are unknown (non-expandable), but
+      // the ranges are derivable from the surrounding hunk headers/counts.
+      const prevOldEnd = prev.oldStart + prev.lines.filter(line => line.oldNum !== null).length - 1
+      const prevNewEnd = prev.newStart + prev.lines.filter(line => line.newNum !== null).length - 1
+      const oldGap = hunk.oldStart - prevOldEnd - 1
+      const newGap = hunk.newStart - prevNewEnd - 1
+      if (oldGap > 0 || newGap > 0) {
+        segments.push({
+          kind: 'fold',
+          count: Math.max(oldGap, newGap, 0),
+          oldStart: prevOldEnd + 1,
+          oldEnd: Math.max(hunk.oldStart - 1, prevOldEnd),
+          newStart: prevNewEnd + 1,
+          newEnd: Math.max(hunk.newStart - 1, prevNewEnd),
+        })
+      }
+    } else if (hunk.oldStart > 1 || hunk.newStart > 1) {
+      // Leading context git trimmed (e.g. -U0 diffs).
+      segments.push({
+        kind: 'fold',
+        count: Math.max(hunk.oldStart - 1, hunk.newStart - 1, 0),
+        oldStart: 1,
+        oldEnd: hunk.oldStart - 1,
+        newStart: 1,
+        newEnd: hunk.newStart - 1,
+      })
+    }
+    segments.push({ kind: 'hunk', rows })
+  })
+  return segments
+}
+
+/** Build the untracked-file shape: one file, one hunk of pure additions. */
+export function untrackedFile(path: string, content: string): DiffFile {
+  const lines: DiffLine[] = []
+  const body = content.endsWith('\n') ? content.slice(0, -1) : content
+  if (body !== '') {
+    let num = 1
+    for (const line of body.split('\n')) {
+      lines.push({ kind: 'add', text: line, oldNum: null, newNum: num })
+      num += 1
+    }
+  }
+  return { oldPath: '/dev/null', newPath: `b/${path}`, binary: false, hunks: [{ oldStart: 0, newStart: 1, header: '', lines }] }
+}
+
+/** Strip the `a/` / `b/` prefix git puts on diff paths (not on /dev/null). */
+export function displayPath(path: string): string {
+  if (path === '/dev/null') return path
+  if (path.startsWith('a/') || path.startsWith('b/')) return path.slice(2)
+  return path
+}
+
+/** The diff's add/del/mod row counts (the "+n −m" header chips). */
+export function diffStats(segments: readonly DiffSegment[]): { added: number; deleted: number } {
+  let added = 0
+  let deleted = 0
+  for (const segment of segments) {
+    if (segment.kind !== 'hunk') continue
+    for (const row of segment.rows) {
+      if (row.kind === 'add' || row.kind === 'mod') added += 1
+      if (row.kind === 'del' || row.kind === 'mod') deleted += 1
+    }
+  }
+  return { added, deleted }
+}
diff --git a/src/client/filetrace/FileTraceTab.tsx b/src/client/filetrace/FileTraceTab.tsx
deleted file mode 100644
index 3341131..0000000
--- a/src/client/filetrace/FileTraceTab.tsx
+++ /dev/null
@@ -1,336 +0,0 @@
-/**
- * The file-trace tab: records every file the model read, wrote, or edited
- * in this session (folded from the session event log) and reviews any op as
- * a line diff (del red / add green / mod blue) or a line-numbered read view,
- * with lightweight syntax coloring whose hues sit between the diff colors.
- * Ported from the standalone dsh-file-trace plugin's panel; the tab can be
- * disabled per user in the Side card settings when the standalone plugin is
- * preferred.
- */
-import { useEffect, useMemo, useRef, useState, type PointerEvent as ReactPointerEvent, type ReactElement, type ReactNode } from 'react'
-import type { SidebarSessionEvent } from '../../context-types.ts'
-import type { TabComponentProps } from '../service.ts'
-import { t } from '../locales.ts'
-import { extractFileOps, groupByFile, knownContentBefore, parseReadLines, type FileOp } from './ops.ts'
-import { diffLines, formatBytes, buildDiffSegments, diffInline, coalesceInline, MIN_FOLD, type DiffRow, type InlineDiff } from './diff.ts'
-import { scanLine, isColored, langOfPath, hasBlockComment, type TokenType, type CodeToken } from './highlight.ts'
-import css from './filetrace.module.css'
-
-/** Long diff lines fold to one ellipsized row; the threshold is the char count. */
-const FOLD_THRESHOLD = 120
-
-/** Cap on accumulated events: the trace shows the recent window, not eternity. */
-const EVENTS_CAP = 4000
-
-/** Token class -> CSS color class ('' inherits the row's diff color). */
-const TOKEN_CLASS: Readonly<Record<TokenType, string>> = {
-  plain: '',
-  comment: css.tokComment ?? '',
-  string: css.tokString ?? '',
-  keyword: css.tokKeyword ?? '',
-  number: css.tokNumber ?? '',
-  type: css.tokType ?? '',
-  function: css.tokFunction ?? '',
-  macro: css.tokMacro ?? '',
-}
-
-/** One token span's class list: its color class, plus the change tint. */
-function tokenSpanClass(type: TokenType, changed: boolean): string {
-  const color = TOKEN_CLASS[type]
-  return changed ? `${color} ${css.inlineChange}` : color
-}
-
-/** Render scanned tokens as colored nodes; uncolored runs stay text. */
-function tokensToNodes(tokens: readonly CodeToken[], changed = false): ReactNode[] {
-  const nodes: ReactNode[] = []
-  for (const token of tokens) {
-    if (!changed && !isColored(token)) nodes.push(token.text)
-    else nodes.push(<span key={String(nodes.length)} className={tokenSpanClass(token.type, changed)}>{token.text}</span>)
-  }
-  return nodes
-}
-
-/** Per-row block-comment entry state for a diff: the old side threads along
- *  old-line order and the new side along new-line order (the LCS row order
- *  preserves both), so multi-line comments color correctly on each side. */
-function diffBlockEntries(rows: readonly DiffRow[], lang: string | undefined): Map<DiffRow, boolean> {
-  const entries = new Map<DiffRow, boolean>()
-  if (!hasBlockComment(lang)) return entries
-  let oldIn = false
-  let newIn = false
-  for (const row of rows) {
-    const isOld = row.oldLine !== undefined
-    const isNew = row.newLine !== undefined
-    entries.set(row, isOld ? oldIn : newIn)
-    if (isOld) oldIn = scanLine(row.text, lang, oldIn).inBlock
-    if (isNew) newIn = scanLine(row.text, lang, newIn).inBlock
-  }
-  return entries
-}
-
-/** Diff material for one operation: an edit reconstructs the full file from
- *  the window's known prior content when possible (hunk-style context); a
- *  write with unknown prior content renders all-added. */
-function diffOf(op: FileOp, prior: string | undefined): readonly DiffRow[] {
-  if (op.kind === 'read') return []
-  if (op.kind === 'edit' && op.edit !== undefined) {
-    const { oldString, newString } = op.edit
-    if (prior !== undefined && prior.includes(oldString)) {
-      const newFile = prior.replace(oldString, newString)
-      return diffLines(prior, newFile)
-    }
-    return diffLines(oldString, newString)
-  }
-  if (op.kind === 'write') {
-    const content = op.content ?? ''
-    const old = prior !== undefined && prior !== content ? prior : undefined
-    return diffLines(old ?? '', content)
-  }
-  return []
-}
-
-/** The file-trace tab body: op list above, selected diff/read pane below. */
-export function FileTraceTab({ ctx, scope, visible }: TabComponentProps) {
-  // The event log snapshot seeds the trace once; live tool/call and
-  // tool/result events append (bounded) and re-extract while visible.
-  const eventsRef = useRef<readonly SidebarSessionEvent[] | null>(null)
-  if (eventsRef.current === null) {
-    eventsRef.current = ctx.sessions.get(scope.sessionId)?.events ?? []
-  }
-  const [tick, setTick] = useState(0)
-  useEffect(() => {
-    if (typeof ctx.on !== 'function') return
-    const off = ctx.on('session/event', (session: unknown, event: SidebarSessionEvent) => {
-      const sessionId = (session as { id?: unknown } | null)?.id
-      if (sessionId !== scope.sessionId) return
-      if (event.type !== 'tool/call' && event.type !== 'tool/result') return
-      const list = [...eventsRef.current ?? [], event]
-      eventsRef.current = list.length > EVENTS_CAP ? list.slice(list.length - EVENTS_CAP) : list
-      if (visible) setTick(value => value + 1)
-    })
-    return () => { off() }
-  }, [ctx, scope.sessionId, visible])
-  // Becoming visible again catches up on events appended while paused.
-  useEffect(() => { if (visible) setTick(value => value + 1) }, [visible])
-
-  const ops = useMemo(() => extractFileOps(eventsRef.current ?? []), [tick])
-  const groups = useMemo(() => groupByFile(ops), [ops])
-  const [selected, setSelected] = useState<{ path: string; op: FileOp } | null>(null)
-  // Long diff lines fold to one ellipsized row; the set holds expanded row keys.
-  const [expandedLines, setExpandedLines] = useState<ReadonlySet<string>>(new Set())
-  // Hunk-fold segments expanded by index; default collapsed.
-  const [expandedFolds, setExpandedFolds] = useState<ReadonlySet<number>>(new Set())
-  // Bottom diff pane height in px; drag the handle to resize (min/max clamp).
-  const [diffHeight, setDiffHeight] = useState(300)
-
-  const selectedOp = selected?.op
-  const selectedLang = useMemo(
-    () => selected === null ? undefined : langOfPath(selected.path),
-    [selected],
-  )
-  const diffRows = useMemo(
-    () => selectedOp === undefined ? [] : diffOf(selectedOp, knownContentBefore(ops, selected?.path ?? '', selectedOp)),
-    [selectedOp, selected?.path, ops],
-  )
-  const segments = useMemo(() => buildDiffSegments(diffRows), [diffRows])
-  // Char-level highlight for mod-row pairs, keyed by (oldLine|newLine).
-  const inlineMap = useMemo(() => {
-    const map = new Map<string, InlineDiff>()
-    let i = 0
-    while (i < diffRows.length) {
-      if (diffRows[i]!.kind !== 'mod') { i += 1; continue }
-      let j = i
-      while (j < diffRows.length && diffRows[j]!.kind === 'mod') j += 1
-      const block = diffRows.slice(i, j)
-      const k = Math.floor(block.length / 2)
-      for (let p = 0; p < k; p += 1) {
-        const delRow = block[p]!
-        const addRow = block[p + k]!
-        const r = diffInline(delRow.text, addRow.text)
-        map.set(`${String(delRow.oldLine ?? '')}|${String(delRow.newLine ?? '')}`, r)
-        map.set(`${String(addRow.oldLine ?? '')}|${String(addRow.newLine ?? '')}`, r)
-      }
-      i = j
-    }
-    return map
-  }, [diffRows])
-  // Block-comment entry state per row, threaded per side.
-  const blockEntries = useMemo(() => diffBlockEntries(diffRows, selectedLang), [diffRows, selectedLang])
-  // Read view rows with block-comment state threaded down the file's lines.
-  const readRows = useMemo(() => {
-    if (selectedOp?.kind !== 'read' || selectedOp.read === undefined) return []
-    let state = false
-    return parseReadLines(selectedOp.read).map((line) => {
-      const scan = scanLine(line.text, selectedLang, state)
-      state = scan.inBlock
-      return { line: line.line, nodes: tokensToNodes(scan.tokens) }
-    })
-  }, [selectedOp, selectedLang])
-  // Reset folding when selecting a different operation.
-  useEffect(() => { setExpandedLines(new Set()); setExpandedFolds(new Set()) }, [selectedOp])
-
-  /** One diff row: colored sign + syntax-colored text, long-line fold toggle. */
-  const renderDiffRow = (row: DiffRow, rowKey: string, lang: string | undefined): ReactElement => {
-    const isLong = row.text.length > FOLD_THRESHOLD
-    const isFolded = isLong && !expandedLines.has(rowKey)
-    const blockEntry = blockEntries.get(row) ?? false
-    return (
-      <div
-        key={rowKey}
-        className={css.diffRow}
-        data-kind={row.kind}
-        data-folded={isFolded ? 'true' : undefined}
-        onClick={isLong ? () => {
-          setExpandedLines(prev => {
-            const next = new Set(prev)
-            if (next.has(rowKey)) next.delete(rowKey)
-            else next.add(rowKey)
-            return next
-          })
-        } : undefined}
-        title={isFolded ? row.text : undefined}
-      >
-        <span className={css.lineNo}>{row.oldLine !== undefined ? String(row.oldLine) : ''}</span>
-        <span className={css.lineNo}>{row.newLine !== undefined ? String(row.newLine) : ''}</span>
-        <span className={css.sign}>{row.kind === 'del' ? '-' : row.kind === 'add' ? '+' : row.kind === 'mod' ? '~' : ' '}</span>
-        <span className={css.text} data-folded={isFolded ? 'true' : undefined}>
-          {row.kind === 'mod' && (() => {
-            const inline = inlineMap.get(`${String(row.oldLine ?? '')}|${String(row.newLine ?? '')}`)
-            if (inline === undefined) return tokensToNodes(scanLine(row.text, lang, blockEntry).tokens)
-            // Coalesced change runs, each split into syntax tokens with
-            // block-comment state threaded across the runs of this line.
-            const side = coalesceInline(row.oldLine !== undefined ? inline.old : inline.next)
-            const nodes: ReactNode[] = []
-            let state = blockEntry
-            for (const seg of side) {
-              const scan = scanLine(seg.text, lang, state)
-              state = scan.inBlock
-              nodes.push(...tokensToNodes(scan.tokens, seg.changed))
-            }
-            return nodes
-          })()}
-          {row.kind !== 'mod' && tokensToNodes(scanLine(row.text, lang, blockEntry).tokens)}
-        </span>
-      </div>
-    )
-  }
-
-  const onHandleDown = (e: ReactPointerEvent<HTMLDivElement>): void => {
-    e.preventDefault()
-    const startY = e.clientY
-    const startH = diffHeight
-    const onMove = (ev: PointerEvent): void => {
-      setDiffHeight(Math.min(Math.max(startH + (startY - ev.clientY), 140), Math.round(window.innerHeight * 0.7)))
-    }
-    const onUp = (): void => {
-      window.removeEventListener('pointermove', onMove)
-      window.removeEventListener('pointerup', onUp)
-    }
-    window.addEventListener('pointermove', onMove)
-    window.addEventListener('pointerup', onUp)
-  }
-
-  return (
-    <div className={css.root}>
-      <div className={css.list}>
-        {ops.length === 0 && <div className={css.empty}>{t('fileTraceEmpty')}</div>}
-        {[...groups.entries()].map(([path, fileOps]) => (
-          <div key={path} className={css.fileGroup}>
-            <div className={css.filePath} title={path}>{path}</div>
-            {fileOps.map(op => (
-              <button
-                type="button"
-                key={op.callId}
-                className={css.opRow}
-                data-op-kind={op.kind}
-                data-op-error={op.isError ? 'true' : undefined}
-                onClick={() => { setSelected({ path, op }) }}
-              >
-                <span className={css.opKind} data-kind={op.kind}>{t(op.kind === 'read' ? 'fileTraceRead' : op.kind === 'write' ? 'fileTraceWrite' : 'fileTraceEdit')}</span>
-                <span className={css.opTime}>{new Date(op.time).toLocaleTimeString()}</span>
-                {op.running && <span className={css.opFlag}>{t('fileTraceRunning')}</span>}
-                {op.isError && <span className={css.opFlagError}>{t('fileTraceError')}</span>}
-                {op.kind !== 'read' && !op.isError && (
-                  <span className={css.opSize}>
-                    {formatBytes(new Blob([op.edit?.newString ?? op.content ?? '']).size)}
-                  </span>
-                )}
-              </button>
-            ))}
-          </div>
-        ))}
-      </div>
-      {selected !== null && (
-        <div className={css.diffPane} style={{ height: diffHeight }}>
-          <div className={css.dragHandle} onPointerDown={onHandleDown} role="separator" aria-orientation="horizontal" />
-          <div className={css.diffHead}>
-            <span className={css.diffPath}>{selected.path}</span>
-            <span className={css.diffKind} data-kind={selected.op.kind}>
-              {t(selected.op.kind === 'read' ? 'fileTraceRead' : selected.op.kind === 'write' ? 'fileTraceWrite' : 'fileTraceEdit')}
-            </span>
-            <button type="button" className={css.close} onClick={() => { setSelected(null) }}>×</button>
-          </div>
-          {selected.op.isError
-            ? (
-              <div className={css.readContent} data-error="true">
-                <div className={css.readError} role="alert">
-                  {selected.op.errorText ?? t('fileTraceError')}
-                </div>
-              </div>
-            )
-            : selected.op.kind === 'read'
-              ? (
-                <div className={css.readContent}>
-                  {readRows.map((row) => (
-                    <div key={String(row.line)} className={css.readRow}>
-                      <span className={css.lineNo}>{String(row.line)}</span>
-                      <span className={css.text}>{row.nodes}</span>
-                    </div>
-                  ))}
-                </div>
-              )
-              : (
-                <div className={css.diffRows}>
-                  {selected.op.kind === 'write'
-                    && knownContentBefore(ops, selected.path, selected.op) === undefined
-                    && <div className={css.priorUnknown}>{t('fileTracePriorUnknown')}</div>}
-                  {segments.map((segment, segIndex) => {
-                    if (segment.kind === 'fold') {
-                      const shouldFold = segment.rows.length >= MIN_FOLD
-                      const isExpanded = expandedFolds.has(segIndex)
-                      if (!shouldFold) {
-                        return segment.rows.map((row, index) => renderDiffRow(row, `${segIndex}-${String(index)}`, selectedLang))
-                      }
-                      return (
-                        <div
-                          key={`fold-${String(segIndex)}`}
-                          className={css.foldRow}
-                          data-expanded={isExpanded ? 'true' : undefined}
-                          onClick={() => {
-                            setExpandedFolds(prev => {
-                              const next = new Set(prev)
-                              if (next.has(segIndex)) next.delete(segIndex)
-                              else next.add(segIndex)
-                              return next
-                            })
-                          }}
-                        >
-                          {isExpanded
-                            ? segment.rows.map((row, index) => renderDiffRow(row, `${segIndex}-${String(index)}`, selectedLang))
-                            : (
-                              <span className={css.foldMarker} title={t('fileTraceContext')}>
-                                {t('fileTraceFold', { count: segment.rows.length })}
-                              </span>
-                            )}
-                        </div>
-                      )
-                    }
-                    return segment.rows.map((row, index) => renderDiffRow(row, `${segIndex}-${String(index)}`, selectedLang))
-                  })}
-                </div>
-              )}
-        </div>
-      )}
-    </div>
-  )
-}
diff --git a/src/client/filetrace/diff.ts b/src/client/filetrace/diff.ts
deleted file mode 100644
index c4500ed..0000000
--- a/src/client/filetrace/diff.ts
+++ /dev/null
@@ -1,257 +0,0 @@
-/**
- * Line-based diff engine for the file-trace panel: an LCS over lines with
- * per-row change classes. Pure functions only — no React, no DOM.
- */
-
-/** One rendered diff row. */
-export interface DiffRow {
-  /** Change class: 'context' shared, 'del' removed, 'add' added, 'mod' rewritten. */
-  readonly kind: 'context' | 'del' | 'add' | 'mod'
-  /** Old-side 1-based line number; absent on pure additions. */
-  readonly oldLine?: number
-  /** New-side 1-based line number; absent on pure deletions. */
-  readonly newLine?: number
-  /** The line's text without its terminator. */
-  readonly text: string
-}
-
-/**
- * Longest-common-subsequence table over line equality.
- * @param oldLines - old side lines.
- * @param newLines - new side lines.
- * @returns the LCS length matrix (rows index oldLines, columns newLines).
- */
-function lcsTable(oldLines: readonly string[], newLines: readonly string[]): number[][] {
-  const table: number[][] = Array.from({ length: oldLines.length + 1 }, () => new Array<number>(newLines.length + 1).fill(0))
-  for (let i = oldLines.length - 1; i >= 0; i -= 1) {
-    for (let j = newLines.length - 1; j >= 0; j -= 1) {
-      table[i]![j] = oldLines[i] === newLines[j]
-        ? table[i + 1]![j + 1]! + 1
-        : Math.max(table[i + 1]![j]!, table[i]![j + 1]!)
-    }
-  }
-  return table
-}
-
-/**
- * Line diff by LCS walk with rewrite pairing: the raw walk emits context/del/
- * add rows; a del-run immediately followed by an add-run marks the overlapping
- * min(len) rows on both sides as 'mod' so rewrites tint distinctly.
- * @param oldText - the previous content; empty string diffs against nothing.
- * @param newText - the next content.
- * @returns ordered diff rows, old-side deletions before new-side additions.
- */
-export function diffLines(oldText: string, newText: string): DiffRow[] {
-  const oldLines = oldText.length === 0 ? [] : oldText.split('\n')
-  const newLines = newText.length === 0 ? [] : newText.split('\n')
-  const table = lcsTable(oldLines, newLines)
-  const raw: DiffRow[] = []
-  let i = 0
-  let j = 0
-  while (i < oldLines.length && j < newLines.length) {
-    if (oldLines[i] === newLines[j]) {
-      raw.push({ kind: 'context', oldLine: i + 1, newLine: j + 1, text: oldLines[i]! })
-      i += 1
-      j += 1
-    } else if (table[i + 1]![j]! >= table[i]![j + 1]!) {
-      raw.push({ kind: 'del', oldLine: i + 1, text: oldLines[i]! })
-      i += 1
-    } else {
-      raw.push({ kind: 'add', newLine: j + 1, text: newLines[j]! })
-      j += 1
-    }
-  }
-  while (i < oldLines.length) {
-    raw.push({ kind: 'del', oldLine: i + 1, text: oldLines[i]! })
-    i += 1
-  }
-  while (j < newLines.length) {
-    raw.push({ kind: 'add', newLine: j + 1, text: newLines[j]! })
-    j += 1
-  }
-  // Post-pass: pair each del-run with the add-run that follows it.
-  const rows = raw.slice()
-  let k = 0
-  while (k < rows.length) {
-    if (rows[k]!.kind !== 'del') { k += 1; continue }
-    const delStart = k
-    while (k < rows.length && rows[k]!.kind === 'del') k += 1
-    const addStart = k
-    while (k < rows.length && rows[k]!.kind === 'add') k += 1
-    const pairs = Math.min(addStart - delStart, k - addStart)
-    for (let p = 0; p < pairs; p += 1) {
-      rows[delStart + p] = { ...rows[delStart + p]!, kind: 'mod' }
-      rows[addStart + p] = { ...rows[addStart + p]!, kind: 'mod' }
-    }
-  }
-  return rows
-}
-
-
-/** One rendered hunk: change rows plus the surrounding context window. */
-export interface DiffHunk { readonly kind: 'hunk'; readonly rows: readonly DiffRow[] }
-
-/** One collapsed run of unchanged context rows (the "… n 行" fold). */
-export interface DiffFold {
-  readonly kind: 'fold'
-  /** The context rows this fold hides; re-render them when expanded. */
-  readonly rows: readonly DiffRow[]
-  readonly oldStart: number
-  readonly oldEnd: number
-  readonly newStart: number
-  readonly newEnd: number
-}
-
-export type DiffSegment = DiffHunk | DiffFold
-
-/** Context window (rows around a change) kept visible in a hunk. */
-export const HUNK_CONTEXT = 3
-
-/** Folded context runs shorter than this are shown directly, not collapsed. */
-export const MIN_FOLD = 3
-
-/**
- * Group a line diff into hunks and folded context runs. Consecutive changes
- * whose gap fits within the context window merge into one hunk; unchanged
- * regions between hunks (and any surrounding the whole diff) become fold
- * segments that default collapsed. This yields the file-hunk presentation
- * familiar from terminal diffs (Claude Code / git hunk headers).
- * @param rows - the flat diff rows.
- * @param context - how many unchanged rows around a change stay visible.
- * @returns ordered segments (hunks and folds).
- */
-export function buildDiffSegments(rows: readonly DiffRow[], context = HUNK_CONTEXT): DiffSegment[] {
-  if (rows.length === 0) return []
-  const changeIndexes = rows.flatMap((row, index) => (row.kind === 'context' ? [] : [index]))
-  if (changeIndexes.length === 0) {
-    // Whole diff is unchanged (or a pure no-op): hide it all behind one fold.
-    return [{ kind: 'fold', rows: [...rows], oldStart: 1, oldEnd: rows.length, newStart: 1, newEnd: rows.length }]
-  }
-  // Cluster changes into runs whose gaps fit within 2*context+1 rows.
-  const hunks: { start: number; end: number }[] = []
-  for (const ci of changeIndexes) {
-    const start = Math.max(0, ci - context)
-    const end = Math.min(rows.length - 1, ci + context)
-    const last = hunks[hunks.length - 1]
-    if (last !== undefined && start <= last.end + 1) {
-      last.end = Math.max(last.end, end)
-    } else {
-      hunks.push({ start, end })
-    }
-  }
-  const segments: DiffSegment[] = []
-  let cursor = 0
-  for (const hunk of hunks) {
-    if (hunk.start > cursor) {
-      const foldRows = rows.slice(cursor, hunk.start)
-      segments.push({
-        kind: 'fold',
-        rows: foldRows,
-        oldStart: firstOldLine(foldRows) ?? (foldRows.length === 0 ? cursor + 1 : cursor + 1),
-        oldEnd: lastOldLine(foldRows) ?? 0,
-        newStart: firstNewLine(foldRows) ?? (foldRows.length === 0 ? cursor + 1 : cursor + 1),
-        newEnd: lastNewLine(foldRows) ?? 0,
-      })
-    }
-    segments.push({ kind: 'hunk', rows: rows.slice(hunk.start, hunk.end + 1) })
-    cursor = hunk.end + 1
-  }
-  if (cursor < rows.length) {
-    const foldRows = rows.slice(cursor)
-    segments.push({
-      kind: 'fold',
-      rows: foldRows,
-      oldStart: firstOldLine(foldRows) ?? cursor + 1,
-      oldEnd: lastOldLine(foldRows) ?? 0,
-      newStart: firstNewLine(foldRows) ?? cursor + 1,
-      newEnd: lastNewLine(foldRows) ?? 0,
-    })
-  }
-  return segments
-}
-
-function firstOldLine(rows: readonly DiffRow[]): number | undefined {
-  for (const row of rows) if (row.oldLine !== undefined) return row.oldLine
-  return undefined
-}
-function lastOldLine(rows: readonly DiffRow[]): number | undefined {
-  for (let i = rows.length - 1; i >= 0; i -= 1) if (rows[i]!.oldLine !== undefined) return rows[i]!.oldLine
-  return undefined
-}
-function firstNewLine(rows: readonly DiffRow[]): number | undefined {
-  for (const row of rows) if (row.newLine !== undefined) return row.newLine
-  return undefined
-}
-function lastNewLine(rows: readonly DiffRow[]): number | undefined {
-  for (let i = rows.length - 1; i >= 0; i -= 1) if (rows[i]!.newLine !== undefined) return rows[i]!.newLine
-  return undefined
-}
-
-/** One intra-line segment: a run of chars with a changed flag. */
-export interface InlineSegment { readonly text: string; readonly changed: boolean }
-/** Each side's intra-line segments. */
-export interface InlineDiff { readonly old: readonly InlineSegment[]; readonly next: readonly InlineSegment[] }
-
-/** Char-diff table guard: above this, inline highlighting is skipped. */
-const INLINE_MAX = 2000
-
-/**
- * Character-level diff between two line texts, used to highlight the exact
- * changed substring inside a "mod" (rewritten) line. Long lines degrade to a
- * single all-changed segment. Pure, no React/DOM.
- * @param oldText - the old line.
- * @param newText - the new line.
- * @returns per-side segments marking changed runs.
- */
-/**
- * Intra-line diff by common prefix/suffix: the shared leading and trailing
- * characters stay unchanged, and only the differing middle is marked changed
- * on both sides. This never highlights identical characters and keeps a small
- * edit inside a long line immediately visible. Pure, no React/DOM.
- * @param oldText - the old line.
- * @param newText - the new line.
- * @returns per-side segments marking changed runs.
- */
-export function diffInline(oldText: string, newText: string): InlineDiff {
-  const minLen = Math.min(oldText.length, newText.length)
-  let prefix = 0
-  while (prefix < minLen && oldText[prefix] === newText[prefix]) prefix += 1
-  let suffix = 0
-  while (suffix < minLen - prefix && oldText[oldText.length - 1 - suffix] === newText[newText.length - 1 - suffix]) suffix += 1
-  const oldMidStart = prefix
-  const oldMidEnd = oldText.length - suffix
-  const newMidStart = prefix
-  const newMidEnd = newText.length - suffix
-  const segments = (text: string, midStart: number, midEnd: number): InlineSegment[] => {
-    const out: InlineSegment[] = []
-    if (midStart > 0) out.push({ text: text.slice(0, midStart), changed: false })
-    const mid = text.slice(midStart, midEnd)
-    if (mid.length > 0) out.push({ text: mid, changed: true })
-    if (midEnd < text.length) out.push({ text: text.slice(midEnd), changed: false })
-    return out
-  }
-  return { old: segments(oldText, oldMidStart, oldMidEnd), next: segments(newText, newMidStart, newMidEnd) }
-}
-
-/**
- * Merge adjacent inline segments sharing the same changed flag, so rendering
- * wraps each run — not each character — in one span.
- * @param segments - the raw per-character-heavy inline segments.
- * @returns coalesced segments; identical text joined into runs.
- */
-export function coalesceInline(segments: readonly InlineSegment[]): InlineSegment[] {
-  const out: InlineSegment[] = []
-  for (const seg of segments) {
-    const last = out[out.length - 1]
-    if (last !== undefined && last.changed === seg.changed) out[out.length - 1] = { text: last.text + seg.text, changed: seg.changed }
-    else out.push(seg)
-  }
-  return out
-}
-
-/** Human byte count for the panel meta row. */
-export function formatBytes(bytes: number): string {
-  if (bytes < 1024) return `${String(bytes)} B`
-  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`
-  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`
-}
\ No newline at end of file
diff --git a/src/client/filetrace/filetrace.module.css b/src/client/filetrace/filetrace.module.css
deleted file mode 100644
index 1032d38..0000000
--- a/src/client/filetrace/filetrace.module.css
+++ /dev/null
@@ -1,76 +0,0 @@
-/* File-trace tab: terminal-style op list + diff pane. Semantic --dsw-alias
-   tokens only (skin contract); the syntax-token hues derive from the alias
-   state tokens via color-mix so they sit BETWEEN the diff colors (violet
-   keywords, teal strings, brand-tinted types, warn-family numbers/functions,
-   magenta macros) instead of colliding with red del / green add / blue mod. */
-
-.root { display: flex; flex-direction: column; min-height: 0; height: 100%; background: var(--dsw-alias-bg-base); color: var(--dsw-alias-label-primary); font-size: 12px; }
-
-.list { flex: 1; min-height: 0; overflow-y: auto; padding: 6px 6px 10px; }
-.empty { color: var(--dsw-alias-label-tertiary); padding: 24px 8px; text-align: center; }
-
-.fileGroup { margin-bottom: 8px; }
-.filePath { display: block; color: var(--dsw-alias-label-secondary); font-family: var(--ds-font-family-code, monospace); font-size: 11px; padding: 2px 4px; word-break: break-all; }
-.opRow { display: flex; align-items: center; gap: 6px; width: 100%; border: 0; border-radius: 6px; background: transparent; color: var(--dsw-alias-label-primary); font: inherit; font-size: 11px; padding: 3px 5px; cursor: pointer; text-align: left; }
-.opRow:hover { background: var(--dsw-alias-interactive-bg-hover); }
-.opKind { border-radius: 4px; font-size: 10px; line-height: 16px; padding: 0 5px; background: var(--dsw-alias-interactive-bg-hover); color: var(--dsw-alias-label-secondary); flex: none; }
-.opKind[data-kind='write'] { color: var(--dsw-alias-state-success-primary); }
-.opKind[data-kind='edit'] { color: var(--dsw-alias-state-business-primary); }
-.opTime { color: var(--dsw-alias-label-tertiary); font-size: 10px; flex: none; }
-.opFlag { color: var(--dsw-alias-state-business-primary); font-size: 10px; flex: none; }
-.opFlagError { color: var(--dsw-alias-state-error-primary); font-size: 10px; flex: none; }
-.opSize { margin-left: auto; color: var(--dsw-alias-label-tertiary); font-size: 10px; flex: none; }
-
-.diffPane { border-top: 1px solid var(--dsw-alias-border-l1); display: flex; flex-direction: column; flex: none; min-height: 0; }
-.dragHandle { flex: none; height: 8px; cursor: ns-resize; position: relative; background: var(--dsw-alias-bg-base); }
-.dragHandle::after { content: ''; position: absolute; left: calc(50% - 18px); top: 3px; width: 36px; height: 2px; border-radius: 1px; background: var(--dsw-alias-border-l2); }
-.dragHandle:hover::after { background: var(--dsw-alias-state-business-primary); }
-.diffHead { display: flex; align-items: center; gap: 6px; padding: 5px 10px; border-bottom: 1px solid var(--dsw-alias-border-l1); }
-.diffPath { flex: 1; font-family: var(--ds-font-family-code, monospace); font-size: 11px; word-break: break-all; color: var(--dsw-alias-label-primary); min-width: 0; }
-.diffKind { flex: none; font-size: 10px; }
-.diffKind[data-kind='write'] { color: var(--dsw-alias-state-success-primary); }
-.diffKind[data-kind='edit'] { color: var(--dsw-alias-state-business-primary); }
-.close { border: 0; border-radius: 6px; background: transparent; color: var(--dsw-alias-label-secondary); font: inherit; cursor: pointer; padding: 1px 6px; flex: none; }
-.close:hover { background: var(--dsw-alias-interactive-bg-hover); color: var(--dsw-alias-label-primary); }
-
-.diffRows { flex: 1; min-height: 0; overflow-y: auto; padding: 4px 0 8px; font-family: var(--ds-font-family-code, monospace); font-size: 11px; }
-.diffRow { display: flex; align-items: flex-start; gap: 5px; padding: 0 8px; line-height: 18px; cursor: default; }
-.diffRow[data-folded='true'] { cursor: pointer; }
-.lineNo { flex: none; width: 2.5em; color: var(--dsw-alias-label-tertiary); text-align: right; user-select: none; font-size: 10px; }
-.sign { flex: none; width: 1em; text-align: center; user-select: none; font-weight: 700; }
-
-.diffRow[data-kind='del'] .sign, .diffRow[data-kind='del'] .text { color: var(--dsw-alias-state-error-primary); }
-.diffRow[data-kind='add'] .sign, .diffRow[data-kind='add'] .text { color: var(--dsw-alias-state-success-primary); }
-.diffRow[data-kind='mod'] .sign, .diffRow[data-kind='mod'] .text { color: var(--dsw-alias-state-business-primary); }
-.diffRow[data-kind='context'] .sign, .diffRow[data-kind='context'] .text { color: var(--dsw-alias-label-secondary); }
-
-.diffRow .text { flex: 1; min-width: 0; white-space: pre-wrap; word-break: break-word; }
-.diffRow[data-folded='true'] .text { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
-
-/* Intra-line changed substring inside a rewritten (mod) line. */
-.inlineChange { background: color-mix(in srgb, var(--dsw-alias-state-business-primary) 26%, transparent); border-radius: 3px; padding: 0 1px; }
-
-/* Syntax-token colors: alias-token mixes between the diff hues. */
-.tokComment { color: var(--dsw-alias-label-tertiary); font-style: italic; }
-.tokKeyword { color: color-mix(in oklab, var(--dsw-alias-state-business-primary) 55%, var(--dsw-alias-state-error-primary)); }
-.tokString { color: color-mix(in oklab, var(--dsw-alias-state-success-primary) 45%, var(--dsw-alias-state-business-primary)); }
-.tokType { color: color-mix(in oklab, var(--dsw-alias-brand-primary) 60%, var(--dsw-alias-state-success-primary)); }
-.tokNumber { color: var(--dsw-alias-state-warn-primary); }
-.tokFunction { color: color-mix(in oklab, var(--dsw-alias-state-warn-primary) 55%, var(--dsw-alias-state-error-primary)); }
-.tokMacro { color: color-mix(in oklab, var(--dsw-alias-state-error-primary) 45%, var(--dsw-alias-state-business-primary)); }
-
-.readContent { flex: 1; min-height: 0; margin: 0; padding: 6px 0 8px; overflow: auto; font-family: var(--ds-font-family-code, monospace); font-size: 11px; line-height: 1.5; }
-.readRow { display: flex; gap: 5px; padding: 0 8px; line-height: 18px; color: var(--dsw-alias-label-primary); }
-.readRow .text { flex: 1; min-width: 0; white-space: pre-wrap; word-break: break-word; }
-.readError { color: var(--dsw-alias-state-error-primary); border-left: 3px solid var(--dsw-alias-state-error-primary); border-radius: 0 6px 6px 0; margin: 6px 8px; padding: 6px 10px; white-space: pre-wrap; word-break: break-word; }
-
-.priorUnknown { color: var(--dsw-alias-label-tertiary); font-size: 10px; padding: 3px 10px; }
-
-/* Hunk-fold row: collapsed marker chip; expanded padding drops to 0 so the
-   revealed rows keep the x-alignment of hunk rows (they carry their own). */
-.foldRow { padding: 0 8px; cursor: pointer; }
-.foldRow[data-expanded='true'] { padding: 0; }
-.foldRow:hover { background: var(--dsw-alias-interactive-bg-hover); }
-.foldMarker { display: inline-block; padding: 2px 6px; border-radius: 4px; margin: 2px 0; color: var(--dsw-alias-label-tertiary); background: var(--dsw-alias-interactive-bg-hover); font-style: italic; }
-.foldRow[data-expanded='true'] { cursor: default; }
-.foldRow[data-expanded='true'] .foldMarker { display: none; }
diff --git a/src/client/locales-ar.ts b/src/client/locales-ar.ts
index a9dbf17..2fecda1 100644
--- a/src/client/locales-ar.ts
+++ b/src/client/locales-ar.ts
@@ -18,18 +18,16 @@
 /** The ar dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const ar: Record<string, string> = {
   files: 'الملفات',
-  fileTrace: 'تتبع الملفات',
-  fileTraceEmpty: 'لا توجد عمليات ملفات في هذه الجلسة بعد',
-  fileTraceRead: 'قراءة',
-  fileTraceWrite: 'كتابة',
-  fileTraceEdit: 'تحرير',
-  fileTraceRunning: 'قيد التنفيذ',
-  fileTraceError: 'خطأ',
-  fileTraceFold: '{count} أسطر… انقر للتوسيع',
-  fileTraceContext: 'سياق',
-  fileTracePriorUnknown: 'المحتوى السابق خارج النافذة؛ يُعرض كما لو أُضيف بالكامل',
+  changesSessionEmpty: 'لا توجد عمليات ملفات في هذه الجلسة بعد',
+  changesRead: 'قراءة',
+  changesWrite: 'كتابة',
+  changesEdit: 'تحرير',
+  changesRunning: 'قيد التنفيذ',
+  changesError: 'خطأ',
+  changesFold: '{count} أسطر… انقر للتوسيع',
+  changesContext: 'سياق',
+  changesPriorUnknown: 'المحتوى السابق خارج النافذة؛ يُعرض كما لو أُضيف بالكامل',
   explorer: 'المستكشف',
-  git: 'إدارة المصدر',
   terminal: 'الطرفية',
   editor: 'المحرّر',
   editorExplorer: 'سلوك فتح الملفات',
@@ -139,7 +137,14 @@ export const ar: Record<string, string> = {
   worktree: 'شجرة العمل',
   checkoutError: 'فشل تبديل الفرع',
   history: 'السجل',
-  changes: 'التغييرات',
+  changes: 'تغييرات الملفات',
+  changesGitLens: 'Git',
+  changesSessionLens: 'الجلسة',
+  changesFilterAll: 'الكل',
+  changesFilterEmpty: 'لا توجد عمليات من هذا النوع',
+  changesOpenDiffTab: 'فتح في تبويب diff منفصل',
+  changesClosePreview: 'إغلاق المعاينة',
+  changesResizePreview: 'تغيير حجم المعاينة',
   staged: 'مُدرج',
   unstaged: 'غير مُدرج',
   cancel: 'إلغاء',
diff --git a/src/client/locales-de.ts b/src/client/locales-de.ts
index faf3456..cb92c75 100644
--- a/src/client/locales-de.ts
+++ b/src/client/locales-de.ts
@@ -3,18 +3,16 @@
  */
 export const de: Record<string, string> = {
   files: 'Dateien',
-  fileTrace: 'Dateiverfolgung',
-  fileTraceEmpty: 'Noch keine Dateioperationen in dieser Sitzung',
-  fileTraceRead: 'Lesen',
-  fileTraceWrite: 'Schreiben',
-  fileTraceEdit: 'Bearbeiten',
-  fileTraceRunning: 'läuft',
-  fileTraceError: 'Fehler',
-  fileTraceFold: '{count} Zeilen… zum Aufklappen klicken',
-  fileTraceContext: 'Kontext',
-  fileTracePriorUnknown: 'Inhalt vor der Änderung liegt außerhalb des Fensters; als vollständig neu angezeigt',
+  changesSessionEmpty: 'Noch keine Dateioperationen in dieser Sitzung',
+  changesRead: 'Lesen',
+  changesWrite: 'Schreiben',
+  changesEdit: 'Bearbeiten',
+  changesRunning: 'läuft',
+  changesError: 'Fehler',
+  changesFold: '{count} Zeilen… zum Aufklappen klicken',
+  changesContext: 'Kontext',
+  changesPriorUnknown: 'Inhalt vor der Änderung liegt außerhalb des Fensters; als vollständig neu angezeigt',
   explorer: 'Explorer',
-  git: 'Quellcodeverwaltung',
   terminal: 'Terminal',
   editor: 'Editor',
   editorExplorer: 'Dateiöffnungsverhalten',
@@ -124,7 +122,14 @@ export const de: Record<string, string> = {
   worktree: 'Worktree',
   checkoutError: 'Branchenwechsel fehlgeschlagen',
   history: 'Verlauf',
-  changes: 'Änderungen',
+  changes: 'Dateiänderungen',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Sitzung',
+  changesFilterAll: 'Alle',
+  changesFilterEmpty: 'Keine Vorgänge dieser Art',
+  changesOpenDiffTab: 'In eigenem Tab öffnen',
+  changesClosePreview: 'Vorschau schließen',
+  changesResizePreview: 'Vorschauhöhe anpassen',
   staged: 'Gestaged',
   unstaged: 'Nicht gestaged',
   cancel: 'Abbrechen',
diff --git a/src/client/locales-fr.ts b/src/client/locales-fr.ts
index ba17e39..cfa4434 100644
--- a/src/client/locales-fr.ts
+++ b/src/client/locales-fr.ts
@@ -10,18 +10,16 @@
 /** fr dictionary for the `betterSidebar` namespace. */
 export const fr: Record<string, string> = {
   files: 'Fichiers',
-  fileTrace: 'Suivi des fichiers',
-  fileTraceEmpty: 'Aucune opération de fichier dans cette session',
-  fileTraceRead: 'Lecture',
-  fileTraceWrite: 'Écriture',
-  fileTraceEdit: 'Modification',
-  fileTraceRunning: 'en cours',
-  fileTraceError: 'erreur',
-  fileTraceFold: '{count} lignes… cliquer pour déplier',
-  fileTraceContext: 'contexte',
-  fileTracePriorUnknown: 'Le contenu antérieur est hors de la fenêtre ; affiché comme entièrement ajouté',
+  changesSessionEmpty: 'Aucune opération de fichier dans cette session',
+  changesRead: 'Lecture',
+  changesWrite: 'Écriture',
+  changesEdit: 'Modification',
+  changesRunning: 'en cours',
+  changesError: 'erreur',
+  changesFold: '{count} lignes… cliquer pour déplier',
+  changesContext: 'contexte',
+  changesPriorUnknown: 'Le contenu antérieur est hors de la fenêtre ; affiché comme entièrement ajouté',
   explorer: 'Explorateur',
-  git: 'Gestion de code source',
   terminal: 'Terminal',
   editor: 'Éditeur',
   editorExplorer: 'Comportement d’ouverture des fichiers',
@@ -132,6 +130,13 @@ export const fr: Record<string, string> = {
   checkoutError: 'Échec du changement de branche',
   history: 'Historique',
   changes: 'Modifications',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Session',
+  changesFilterAll: 'Tout',
+  changesFilterEmpty: 'Aucune opération de ce type',
+  changesOpenDiffTab: 'Ouvrir dans un onglet diff',
+  changesClosePreview: 'Fermer l\'aperçu',
+  changesResizePreview: 'Redimensionner l\'aperçu',
   staged: 'En scène',
   unstaged: 'Hors scène',
   cancel: 'Annuler',
diff --git a/src/client/locales-hi.ts b/src/client/locales-hi.ts
index 79050a3..36ef5e9 100644
--- a/src/client/locales-hi.ts
+++ b/src/client/locales-hi.ts
@@ -17,18 +17,16 @@
 /** The hi dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const hi: Record<string, string> = {
   files: 'फ़ाइलें',
-  fileTrace: 'फ़ाइल ट्रेस',
-  fileTraceEmpty: 'इस सत्र में अभी कोई फ़ाइल ऑपरेशन नहीं',
-  fileTraceRead: 'पढ़ना',
-  fileTraceWrite: 'लिखना',
-  fileTraceEdit: 'संपादन',
-  fileTraceRunning: 'चल रहा है',
-  fileTraceError: 'त्रुटि',
-  fileTraceFold: '{count} पंक्तियाँ… विस्तार के लिए क्लिक करें',
-  fileTraceContext: 'संदर्भ',
-  fileTracePriorUnknown: 'बदलाव से पहले की सामग्री विंडो में नहीं है; पूरी नई जोड़ी गई दिखाई जाती है',
+  changesSessionEmpty: 'इस सत्र में अभी कोई फ़ाइल ऑपरेशन नहीं',
+  changesRead: 'पढ़ना',
+  changesWrite: 'लिखना',
+  changesEdit: 'संपादन',
+  changesRunning: 'चल रहा है',
+  changesError: 'त्रुटि',
+  changesFold: '{count} पंक्तियाँ… विस्तार के लिए क्लिक करें',
+  changesContext: 'संदर्भ',
+  changesPriorUnknown: 'बदलाव से पहले की सामग्री विंडो में नहीं है; पूरी नई जोड़ी गई दिखाई जाती है',
   explorer: 'एक्सप्लोरर',
-  git: 'सोर्स कंट्रोल',
   terminal: 'टर्मिनल',
   editor: 'एडिटर',
   editorExplorer: 'फ़ाइल खोलने का तरीका',
@@ -138,7 +136,14 @@ export const hi: Record<string, string> = {
   worktree: 'वर्कट्री',
   checkoutError: 'ब्रांच स्विच विफल',
   history: 'इतिहास',
-  changes: 'बदलाव',
+  changes: 'फ़ाइल परिवर्तन',
+  changesGitLens: 'Git',
+  changesSessionLens: 'सेशन',
+  changesFilterAll: 'सभी',
+  changesFilterEmpty: 'इस प्रकार का कोई ऑपरेशन नहीं',
+  changesOpenDiffTab: 'अलग diff टैब में खोलें',
+  changesClosePreview: 'पूर्वावलोकन बंद करें',
+  changesResizePreview: 'पूर्वावलोकन का आकार बदलें',
   staged: 'स्टेज किया',
   unstaged: 'अनस्टेज',
   cancel: 'रद्द करें',
diff --git a/src/client/locales-id.ts b/src/client/locales-id.ts
index b1792b1..9f859dc 100644
--- a/src/client/locales-id.ts
+++ b/src/client/locales-id.ts
@@ -15,18 +15,16 @@
 
 export const id: Record<string, string> = {
   files: 'Berkas',
-  fileTrace: 'Pelacakan file',
-  fileTraceEmpty: 'Belum ada operasi file di sesi ini',
-  fileTraceRead: 'Baca',
-  fileTraceWrite: 'Tulis',
-  fileTraceEdit: 'Edit',
-  fileTraceRunning: 'berjalan',
-  fileTraceError: 'error',
-  fileTraceFold: '{count} baris… klik untuk meluaskan',
-  fileTraceContext: 'konteks',
-  fileTracePriorUnknown: 'Konten sebelum perubahan berada di luar jendela; ditampilkan sebagai sepenuhnya baru',
+  changesSessionEmpty: 'Belum ada operasi file di sesi ini',
+  changesRead: 'Baca',
+  changesWrite: 'Tulis',
+  changesEdit: 'Edit',
+  changesRunning: 'berjalan',
+  changesError: 'error',
+  changesFold: '{count} baris… klik untuk meluaskan',
+  changesContext: 'konteks',
+  changesPriorUnknown: 'Konten sebelum perubahan berada di luar jendela; ditampilkan sebagai sepenuhnya baru',
   explorer: 'Explorer',
-  git: 'Source Control',
   terminal: 'Terminal',
   editor: 'Editor',
   editorExplorer: 'Perilaku buka berkas',
@@ -136,7 +134,14 @@ export const id: Record<string, string> = {
   worktree: 'Worktree',
   checkoutError: 'Beralih branch gagal',
   history: 'Riwayat',
-  changes: 'Perubahan',
+  changes: 'Perubahan berkas',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Sesi',
+  changesFilterAll: 'Semua',
+  changesFilterEmpty: 'Tidak ada operasi jenis ini',
+  changesOpenDiffTab: 'Buka di tab diff terpisah',
+  changesClosePreview: 'Tutup pratinjau',
+  changesResizePreview: 'Ubah ukuran pratinjau',
   staged: 'Staged',
   unstaged: 'Unstaged',
   cancel: 'Batal',
diff --git a/src/client/locales-it.ts b/src/client/locales-it.ts
index d926304..7ca8dc0 100644
--- a/src/client/locales-it.ts
+++ b/src/client/locales-it.ts
@@ -8,18 +8,16 @@
 
 export const it: Record<string, string> = {
   files: 'File',
-  fileTrace: 'Tracciatura file',
-  fileTraceEmpty: 'Ancora nessuna operazione sui file in questa sessione',
-  fileTraceRead: 'Lettura',
-  fileTraceWrite: 'Scrittura',
-  fileTraceEdit: 'Modifica',
-  fileTraceRunning: 'in esecuzione',
-  fileTraceError: 'errore',
-  fileTraceFold: '{count} righe… clicca per espandere',
-  fileTraceContext: 'contesto',
-  fileTracePriorUnknown: 'Il contenuto precedente è fuori dalla finestra; mostrato come interamente aggiunto',
+  changesSessionEmpty: 'Ancora nessuna operazione sui file in questa sessione',
+  changesRead: 'Lettura',
+  changesWrite: 'Scrittura',
+  changesEdit: 'Modifica',
+  changesRunning: 'in esecuzione',
+  changesError: 'errore',
+  changesFold: '{count} righe… clicca per espandere',
+  changesContext: 'contesto',
+  changesPriorUnknown: 'Il contenuto precedente è fuori dalla finestra; mostrato come interamente aggiunto',
   explorer: 'Esplora risorse',
-  git: 'Controllo del codice sorgente',
   terminal: 'Terminale',
   editor: 'Editor',
   editorExplorer: 'Modalità di apertura dei file',
@@ -130,6 +128,13 @@ export const it: Record<string, string> = {
   checkoutError: 'Cambio di ramo non riuscito',
   history: 'Cronologia',
   changes: 'Modifiche',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Sessione',
+  changesFilterAll: 'Tutti',
+  changesFilterEmpty: 'Nessuna operazione di questo tipo',
+  changesOpenDiffTab: 'Apri in una scheda diff',
+  changesClosePreview: 'Ridimensiona l\'anteprima',
+  changesResizePreview: 'Ridimensiona anteprima',
   staged: 'In stage',
   unstaged: 'Non in stage',
   cancel: 'Annulla',
diff --git a/src/client/locales-ja.ts b/src/client/locales-ja.ts
index 93edb2d..1abf67e 100644
--- a/src/client/locales-ja.ts
+++ b/src/client/locales-ja.ts
@@ -17,18 +17,16 @@
 /** The ja dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const ja: Record<string, string> = {
   files: 'ファイル',
-  fileTrace: 'ファイル追跡',
-  fileTraceEmpty: 'このセッションにはファイル操作がまだありません',
-  fileTraceRead: '読み取り',
-  fileTraceWrite: '書き込み',
-  fileTraceEdit: '編集',
-  fileTraceRunning: '実行中',
-  fileTraceError: 'エラー',
-  fileTraceFold: '{count} 行…クリックで展開',
-  fileTraceContext: 'コンテキスト',
-  fileTracePriorUnknown: '変更前の内容がウィンドウ内になく、すべて新規追加として表示されます',
+  changesSessionEmpty: 'このセッションにはファイル操作がまだありません',
+  changesRead: '読み取り',
+  changesWrite: '書き込み',
+  changesEdit: '編集',
+  changesRunning: '実行中',
+  changesError: 'エラー',
+  changesFold: '{count} 行…クリックで展開',
+  changesContext: 'コンテキスト',
+  changesPriorUnknown: '変更前の内容がウィンドウ内になく、すべて新規追加として表示されます',
   explorer: 'エクスプローラー',
-  git: 'ソース管理',
   terminal: 'ターミナル',
   editor: 'エディター',
   editorExplorer: 'ファイルの開き方',
@@ -138,7 +136,14 @@ export const ja: Record<string, string> = {
   worktree: 'ワークツリー',
   checkoutError: 'ブランチ切り替えに失敗',
   history: '履歴',
-  changes: '変更',
+  changes: 'ファイル変更',
+  changesGitLens: 'Git',
+  changesSessionLens: 'セッション',
+  changesFilterAll: 'すべて',
+  changesFilterEmpty: 'この種類の操作はありません',
+  changesOpenDiffTab: '独立タブで開く',
+  changesClosePreview: 'プレビューを閉じる',
+  changesResizePreview: 'プレビューの高さを変更',
   staged: 'ステージ済み',
   unstaged: '未ステージ',
   cancel: 'キャンセル',
diff --git a/src/client/locales-ko.ts b/src/client/locales-ko.ts
index dcff37a..4ae68fe 100644
--- a/src/client/locales-ko.ts
+++ b/src/client/locales-ko.ts
@@ -9,18 +9,16 @@
 
 export const ko: Record<string, string> = {
   files: '파일',
-  fileTrace: '파일 추적',
-  fileTraceEmpty: '이 세션에 아직 파일 작업이 없습니다',
-  fileTraceRead: '읽기',
-  fileTraceWrite: '쓰기',
-  fileTraceEdit: '편집',
-  fileTraceRunning: '실행 중',
-  fileTraceError: '오류',
-  fileTraceFold: '{count}줄… 클릭하여 펼치기',
-  fileTraceContext: '컨텍스트',
-  fileTracePriorUnknown: '변경 전 내용이 창에 없어 모두 새로 추가된 것으로 표시됩니다',
+  changesSessionEmpty: '이 세션에 아직 파일 작업이 없습니다',
+  changesRead: '읽기',
+  changesWrite: '쓰기',
+  changesEdit: '편집',
+  changesRunning: '실행 중',
+  changesError: '오류',
+  changesFold: '{count}줄… 클릭하여 펼치기',
+  changesContext: '컨텍스트',
+  changesPriorUnknown: '변경 전 내용이 창에 없어 모두 새로 추가된 것으로 표시됩니다',
   explorer: '탐색기',
-  git: '소스 제어',
   terminal: '터미널',
   editor: '편집기',
   editorExplorer: '파일 열기 방식',
@@ -130,7 +128,14 @@ export const ko: Record<string, string> = {
   worktree: '워크트리',
   checkoutError: '브랜치 전환 실패',
   history: '기록',
-  changes: '변경 사항',
+  changes: '파일 변경',
+  changesGitLens: 'Git',
+  changesSessionLens: '세션',
+  changesFilterAll: '모두',
+  changesFilterEmpty: '이 종류의 작업이 없습니다',
+  changesOpenDiffTab: '별도 탭에서 열기',
+  changesClosePreview: '미리보기 닫기',
+  changesResizePreview: '미리보기 높이 조정',
   staged: '스테이징됨',
   unstaged: '스테이징 안 됨',
   cancel: '취소',
diff --git a/src/client/locales-nl.ts b/src/client/locales-nl.ts
index 8049339..99734a7 100644
--- a/src/client/locales-nl.ts
+++ b/src/client/locales-nl.ts
@@ -15,18 +15,16 @@
  */
 export const nl: Record<string, string> = {
   files: 'Bestanden',
-  fileTrace: 'Bestandsspoor',
-  fileTraceEmpty: 'Nog geen bestandsbewerkingen in deze sessie',
-  fileTraceRead: 'Lezen',
-  fileTraceWrite: 'Schrijven',
-  fileTraceEdit: 'Bewerken',
-  fileTraceRunning: 'actief',
-  fileTraceError: 'fout',
-  fileTraceFold: '{count} regels… klik om uit te klappen',
-  fileTraceContext: 'context',
-  fileTracePriorUnknown: 'Eerdere inhoud valt buiten het venster; getoond als volledig nieuw',
+  changesSessionEmpty: 'Nog geen bestandsbewerkingen in deze sessie',
+  changesRead: 'Lezen',
+  changesWrite: 'Schrijven',
+  changesEdit: 'Bewerken',
+  changesRunning: 'actief',
+  changesError: 'fout',
+  changesFold: '{count} regels… klik om uit te klappen',
+  changesContext: 'context',
+  changesPriorUnknown: 'Eerdere inhoud valt buiten het venster; getoond als volledig nieuw',
   explorer: 'Verkenner',
-  git: 'Bronbeheer',
   terminal: 'Terminal',
   editor: 'Editor',
   editorExplorer: 'Bestand openingsgedrag',
@@ -136,7 +134,14 @@ export const nl: Record<string, string> = {
   worktree: 'Worktree',
   checkoutError: 'Wisselen van branch mislukt',
   history: 'Geschiedenis',
-  changes: 'Wijzigingen',
+  changes: 'Bestandswijzigingen',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Sessie',
+  changesFilterAll: 'Alles',
+  changesFilterEmpty: 'Geen bewerkingen van dit soort',
+  changesOpenDiffTab: 'In eigen diff-tabblad openen',
+  changesClosePreview: 'Voorbeeld sluiten',
+  changesResizePreview: 'Voorbeeld vergroten/verkleinen',
   staged: 'Gestaged',
   unstaged: 'Niet gestaged',
   cancel: 'Annuleren',
diff --git a/src/client/locales-pl.ts b/src/client/locales-pl.ts
index c6c2aa0..f24d3ed 100644
--- a/src/client/locales-pl.ts
+++ b/src/client/locales-pl.ts
@@ -19,18 +19,16 @@
 /** The pl dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const pl: Record<string, string> = {
   files: 'Pliki',
-  fileTrace: 'Śledzenie plików',
-  fileTraceEmpty: 'Brak operacji na plikach w tej sesji',
-  fileTraceRead: 'Odczyt',
-  fileTraceWrite: 'Zapis',
-  fileTraceEdit: 'Edycja',
-  fileTraceRunning: 'w toku',
-  fileTraceError: 'błąd',
-  fileTraceFold: '{count} wierszy… kliknij, aby rozwinąć',
-  fileTraceContext: 'kontekst',
-  fileTracePriorUnknown: 'Zawartość sprzed zmiany jest poza oknem; pokazana jako w całości nowa',
+  changesSessionEmpty: 'Brak operacji na plikach w tej sesji',
+  changesRead: 'Odczyt',
+  changesWrite: 'Zapis',
+  changesEdit: 'Edycja',
+  changesRunning: 'w toku',
+  changesError: 'błąd',
+  changesFold: '{count} wierszy… kliknij, aby rozwinąć',
+  changesContext: 'kontekst',
+  changesPriorUnknown: 'Zawartość sprzed zmiany jest poza oknem; pokazana jako w całości nowa',
   explorer: 'Eksplorator',
-  git: 'Kontrola źródła',
   terminal: 'Terminal',
   editor: 'Edytor',
   editorExplorer: 'Sposób otwierania plików',
@@ -140,7 +138,14 @@ export const pl: Record<string, string> = {
   worktree: 'Drzewo robocze',
   checkoutError: 'Przełączenie gałęzi nie powiodło się',
   history: 'Historia',
-  changes: 'Zmiany',
+  changes: 'Zmiany plików',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Sesja',
+  changesFilterAll: 'Wszystko',
+  changesFilterEmpty: 'Brak operacji tego rodzaju',
+  changesOpenDiffTab: 'Otwórz w osobnej karcie',
+  changesClosePreview: 'Zamknij podgląd',
+  changesResizePreview: 'Zmień wysokość podglądu',
   staged: 'W indeksie',
   unstaged: 'Poza indeksem',
   cancel: 'Anuluj',
diff --git a/src/client/locales-pt.ts b/src/client/locales-pt.ts
index 3684eac..143105a 100644
--- a/src/client/locales-pt.ts
+++ b/src/client/locales-pt.ts
@@ -1,17 +1,15 @@
 export const pt: Record<string, string> = {
   files: 'Arquivos',
-  fileTrace: 'Rastreio de arquivos',
-  fileTraceEmpty: 'Ainda sem operações de arquivo nesta sessão',
-  fileTraceRead: 'Leitura',
-  fileTraceWrite: 'Escrita',
-  fileTraceEdit: 'Edição',
-  fileTraceRunning: 'em execução',
-  fileTraceError: 'erro',
-  fileTraceFold: '{count} linhas… clique para expandir',
-  fileTraceContext: 'contexto',
-  fileTracePriorUnknown: 'O conteúdo anterior está fora da janela; mostrado como totalmente adicionado',
+  changesSessionEmpty: 'Ainda sem operações de arquivo nesta sessão',
+  changesRead: 'Leitura',
+  changesWrite: 'Escrita',
+  changesEdit: 'Edição',
+  changesRunning: 'em execução',
+  changesError: 'erro',
+  changesFold: '{count} linhas… clique para expandir',
+  changesContext: 'contexto',
+  changesPriorUnknown: 'O conteúdo anterior está fora da janela; mostrado como totalmente adicionado',
   explorer: 'Explorador',
-  git: 'Controle de código-fonte',
   terminal: 'Terminal',
   editor: 'Editor',
   editorExplorer: 'Comportamento de abertura de arquivos',
@@ -122,6 +120,13 @@ export const pt: Record<string, string> = {
   checkoutError: 'Falha ao alternar de branch',
   history: 'Histórico',
   changes: 'Alterações',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Sessão',
+  changesFilterAll: 'Tudo',
+  changesFilterEmpty: 'Nenhuma operação deste tipo',
+  changesOpenDiffTab: 'Abrir em uma aba de diff',
+  changesClosePreview: 'Fechar prévia',
+  changesResizePreview: 'Ajustar altura da prévia',
   staged: 'Preparadas',
   unstaged: 'Não preparadas',
   cancel: 'Cancelar',
diff --git a/src/client/locales-ru.ts b/src/client/locales-ru.ts
index 78baecf..33c5c2a 100644
--- a/src/client/locales-ru.ts
+++ b/src/client/locales-ru.ts
@@ -13,18 +13,16 @@
 
 export const ru: Record<string, string> = {
   files: 'Файлы',
-  fileTrace: 'Отслеживание файлов',
-  fileTraceEmpty: 'В этой сессии пока нет файловых операций',
-  fileTraceRead: 'Чтение',
-  fileTraceWrite: 'Запись',
-  fileTraceEdit: 'Изменение',
-  fileTraceRunning: 'выполняется',
-  fileTraceError: 'ошибка',
-  fileTraceFold: '{count} строк… нажмите, чтобы развернуть',
-  fileTraceContext: 'контекст',
-  fileTracePriorUnknown: 'Содержимое до изменения вне окна; показано как полностью добавленное',
+  changesSessionEmpty: 'В этой сессии пока нет файловых операций',
+  changesRead: 'Чтение',
+  changesWrite: 'Запись',
+  changesEdit: 'Изменение',
+  changesRunning: 'выполняется',
+  changesError: 'ошибка',
+  changesFold: '{count} строк… нажмите, чтобы развернуть',
+  changesContext: 'контекст',
+  changesPriorUnknown: 'Содержимое до изменения вне окна; показано как полностью добавленное',
   explorer: 'Проводник',
-  git: 'Контроль версий',
   terminal: 'Терминал',
   editor: 'Редактор',
   editorExplorer: 'Способ открытия файлов',
@@ -134,7 +132,14 @@ export const ru: Record<string, string> = {
   worktree: 'Рабочее дерево',
   checkoutError: 'Сбой переключения ветки',
   history: 'История',
-  changes: 'Изменения',
+  changes: 'Изменения файлов',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Сессия',
+  changesFilterAll: 'Все',
+  changesFilterEmpty: 'Нет операций этого типа',
+  changesOpenDiffTab: 'Открыть в отдельной вкладке',
+  changesClosePreview: 'Закрыть просмотр',
+  changesResizePreview: 'Изменить высоту просмотра',
   staged: 'В индексе',
   unstaged: 'Не в индексе',
   cancel: 'Отмена',
diff --git a/src/client/locales-sv.ts b/src/client/locales-sv.ts
index 5ce9b75..1f7f16a 100644
--- a/src/client/locales-sv.ts
+++ b/src/client/locales-sv.ts
@@ -1,17 +1,15 @@
 export const sv: Record<string, string> = {
   files: 'Filer',
-  fileTrace: 'Filspårning',
-  fileTraceEmpty: 'Inga filoperationer i den här sessionen ännu',
-  fileTraceRead: 'Läs',
-  fileTraceWrite: 'Skriv',
-  fileTraceEdit: 'Redigera',
-  fileTraceRunning: 'körs',
-  fileTraceError: 'fel',
-  fileTraceFold: '{count} rader… klicka för att expandera',
-  fileTraceContext: 'kontext',
-  fileTracePriorUnknown: 'Innehållet före ändringen ligger utanför fönstret; visas som helt nytt',
+  changesSessionEmpty: 'Inga filoperationer i den här sessionen ännu',
+  changesRead: 'Läs',
+  changesWrite: 'Skriv',
+  changesEdit: 'Redigera',
+  changesRunning: 'körs',
+  changesError: 'fel',
+  changesFold: '{count} rader… klicka för att expandera',
+  changesContext: 'kontext',
+  changesPriorUnknown: 'Innehållet före ändringen ligger utanför fönstret; visas som helt nytt',
   explorer: 'Utforskare',
-  git: 'Källkodshantering',
   terminal: 'Terminal',
   editor: 'Editor',
   editorExplorer: 'Filers öppningsbeteende',
@@ -121,7 +119,14 @@ export const sv: Record<string, string> = {
   worktree: 'Arbetsträd',
   checkoutError: 'Grenbyte misslyckades',
   history: 'Historik',
-  changes: 'Ändringar',
+  changes: 'Filändringar',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Session',
+  changesFilterAll: 'Alla',
+  changesFilterEmpty: 'Inga åtgärder av denna typ',
+  changesOpenDiffTab: 'Öppna i egen diff-flik',
+  changesClosePreview: 'Stäng förhandsvisning',
+  changesResizePreview: 'Ändra storlek på förhandsvisningen',
   staged: 'Köade',
   unstaged: 'Avköade',
   cancel: 'Avbryt',
diff --git a/src/client/locales-th.ts b/src/client/locales-th.ts
index a463c22..8bafaad 100644
--- a/src/client/locales-th.ts
+++ b/src/client/locales-th.ts
@@ -17,18 +17,16 @@
 /** The th dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const th: Record<string, string> = {
   files: 'ไฟล์',
-  fileTrace: 'ติดตามไฟล์',
-  fileTraceEmpty: 'ยังไม่มีการดำเนินการไฟล์ในเซสชันนี้',
-  fileTraceRead: 'อ่าน',
-  fileTraceWrite: 'เขียน',
-  fileTraceEdit: 'แก้ไข',
-  fileTraceRunning: 'กำลังทำงาน',
-  fileTraceError: 'ข้อผิดพลาด',
-  fileTraceFold: '{count} บรรทัด… คลิกเพื่อขยาย',
-  fileTraceContext: 'บริบท',
-  fileTracePriorUnknown: 'เนื้อหาก่อนแก้ไขอยู่นอกหน้าต่าง แสดงเป็นเพิ่มใหม่ทั้งหมด',
+  changesSessionEmpty: 'ยังไม่มีการดำเนินการไฟล์ในเซสชันนี้',
+  changesRead: 'อ่าน',
+  changesWrite: 'เขียน',
+  changesEdit: 'แก้ไข',
+  changesRunning: 'กำลังทำงาน',
+  changesError: 'ข้อผิดพลาด',
+  changesFold: '{count} บรรทัด… คลิกเพื่อขยาย',
+  changesContext: 'บริบท',
+  changesPriorUnknown: 'เนื้อหาก่อนแก้ไขอยู่นอกหน้าต่าง แสดงเป็นเพิ่มใหม่ทั้งหมด',
   explorer: 'ตัวสำรวจ',
-  git: 'การควบคุมซอร์ส',
   terminal: 'เทอร์มินัล',
   editor: 'ตัวแก้ไข',
   editorExplorer: 'พฤติกรรมการเปิดไฟล์',
@@ -138,7 +136,14 @@ export const th: Record<string, string> = {
   worktree: 'เวิร์กทรี',
   checkoutError: 'สลับ branch ล้มเหลว',
   history: 'ประวัติ',
-  changes: 'การเปลี่ยนแปลง',
+  changes: 'การเปลี่ยนแปลงไฟล์',
+  changesGitLens: 'Git',
+  changesSessionLens: 'เซสชัน',
+  changesFilterAll: 'ทั้งหมด',
+  changesFilterEmpty: 'ไม่มีการดำเนินการประเภทนี้',
+  changesOpenDiffTab: 'เปิดในแท็บ diff แยก',
+  changesClosePreview: 'ปิดตัวอย่าง',
+  changesResizePreview: 'ปรับขนาดตัวอย่าง',
   staged: 'Staged',
   unstaged: 'Unstaged',
   cancel: 'ยกเลิก',
diff --git a/src/client/locales-tr.ts b/src/client/locales-tr.ts
index 23e6a9e..658809f 100644
--- a/src/client/locales-tr.ts
+++ b/src/client/locales-tr.ts
@@ -17,18 +17,16 @@
 /** The tr dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const tr: Record<string, string> = {
   files: 'Dosyalar',
-  fileTrace: 'Dosya izleme',
-  fileTraceEmpty: 'Bu oturumda henüz dosya işlemi yok',
-  fileTraceRead: 'Okuma',
-  fileTraceWrite: 'Yazma',
-  fileTraceEdit: 'Düzenleme',
-  fileTraceRunning: 'çalışıyor',
-  fileTraceError: 'hata',
-  fileTraceFold: '{count} satır… genişletmek için tıklayın',
-  fileTraceContext: 'bağlam',
-  fileTracePriorUnknown: 'Değişiklik öncesi içerik pencere dışında; tamamen yeni eklenmiş olarak gösteriliyor',
+  changesSessionEmpty: 'Bu oturumda henüz dosya işlemi yok',
+  changesRead: 'Okuma',
+  changesWrite: 'Yazma',
+  changesEdit: 'Düzenleme',
+  changesRunning: 'çalışıyor',
+  changesError: 'hata',
+  changesFold: '{count} satır… genişletmek için tıklayın',
+  changesContext: 'bağlam',
+  changesPriorUnknown: 'Değişiklik öncesi içerik pencere dışında; tamamen yeni eklenmiş olarak gösteriliyor',
   explorer: 'Gezgin',
-  git: 'Kaynak denetimi',
   terminal: 'Terminal',
   editor: 'Düzenleyici',
   editorExplorer: 'Dosya açma davranışı',
@@ -138,7 +136,14 @@ export const tr: Record<string, string> = {
   worktree: 'Çalışma ağacı',
   checkoutError: 'Dal değiştirme başarısız',
   history: 'Geçmiş',
-  changes: 'Değişiklikler',
+  changes: 'Dosya değişiklikleri',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Oturum',
+  changesFilterAll: 'Tümü',
+  changesFilterEmpty: 'Bu türde işlem yok',
+  changesOpenDiffTab: 'Ayrı bir diff sekmesinde aç',
+  changesClosePreview: 'Önizlemeyi kapat',
+  changesResizePreview: 'Önizlemeyi boyutlandır',
   staged: 'Sahnelendi',
   unstaged: 'Sahnelenmedi',
   cancel: 'İptal',
diff --git a/src/client/locales-vi.ts b/src/client/locales-vi.ts
index c5bfc5a..46eb488 100644
--- a/src/client/locales-vi.ts
+++ b/src/client/locales-vi.ts
@@ -17,18 +17,16 @@
 /** The vi dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const vi: Record<string, string> = {
   files: 'Tệp',
-  fileTrace: 'Theo dõi tệp',
-  fileTraceEmpty: 'Chưa có thao tác tệp nào trong phiên này',
-  fileTraceRead: 'Đọc',
-  fileTraceWrite: 'Ghi',
-  fileTraceEdit: 'Chỉnh sửa',
-  fileTraceRunning: 'đang chạy',
-  fileTraceError: 'lỗi',
-  fileTraceFold: '{count} dòng… bấm để mở rộng',
-  fileTraceContext: 'ngữ cảnh',
-  fileTracePriorUnknown: 'Nội dung trước thay đổi nằm ngoài cửa sổ; hiển thị như toàn bộ mới thêm',
+  changesSessionEmpty: 'Chưa có thao tác tệp nào trong phiên này',
+  changesRead: 'Đọc',
+  changesWrite: 'Ghi',
+  changesEdit: 'Chỉnh sửa',
+  changesRunning: 'đang chạy',
+  changesError: 'lỗi',
+  changesFold: '{count} dòng… bấm để mở rộng',
+  changesContext: 'ngữ cảnh',
+  changesPriorUnknown: 'Nội dung trước thay đổi nằm ngoài cửa sổ; hiển thị như toàn bộ mới thêm',
   explorer: 'Trình khám phá',
-  git: 'Quản lý mã nguồn',
   terminal: 'Terminal',
   editor: 'Trình soạn thảo',
   editorExplorer: 'Cách mở tệp',
@@ -138,7 +136,14 @@ export const vi: Record<string, string> = {
   worktree: 'Worktree',
   checkoutError: 'Chuyển branch thất bại',
   history: 'Lịch sử',
-  changes: 'Thay đổi',
+  changes: 'Thay đổi tệp',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Phiên',
+  changesFilterAll: 'Tất cả',
+  changesFilterEmpty: 'Không có thao tác thuộc loại này',
+  changesOpenDiffTab: 'Mở trong tab diff riêng',
+  changesClosePreview: 'Đóng xem trước',
+  changesResizePreview: 'Điều chỉnh kích thước xem trước',
   staged: 'Đã stage',
   unstaged: 'Chưa stage',
   cancel: 'Hủy',
diff --git a/src/client/locales-zh-HK.ts b/src/client/locales-zh-HK.ts
index f0b5ddb..9d5a1e4 100644
--- a/src/client/locales-zh-HK.ts
+++ b/src/client/locales-zh-HK.ts
@@ -32,18 +32,16 @@
 /** The zh-HK dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const zhHK: Record<string, string> = {
   files: '檔案',
-  fileTrace: '檔案追蹤',
-  fileTraceEmpty: '本工作階段還沒有檔案操作',
-  fileTraceRead: '讀取',
-  fileTraceWrite: '寫入',
-  fileTraceEdit: '編輯',
-  fileTraceRunning: '執行中',
-  fileTraceError: '出錯',
-  fileTraceFold: '{count} 行…點擊展開',
-  fileTraceContext: '上下文',
-  fileTracePriorUnknown: '變更前的內容不在視窗內，顯示為全部新增',
+  changesSessionEmpty: '本工作階段還沒有檔案操作',
+  changesRead: '讀取',
+  changesWrite: '寫入',
+  changesEdit: '編輯',
+  changesRunning: '執行中',
+  changesError: '出錯',
+  changesFold: '{count} 行…點擊展開',
+  changesContext: '上下文',
+  changesPriorUnknown: '變更前的內容不在視窗內，顯示為全部新增',
   explorer: '檔案總管',
-  git: '原始碼管理',
   terminal: '終端',
   editor: '編輯器',
   editorExplorer: '檔案開啟方式',
@@ -153,7 +151,14 @@ export const zhHK: Record<string, string> = {
   worktree: '工作樹',
   checkoutError: '切換分支失敗',
   history: '歷史',
-  changes: '變更',
+  changes: '檔案變動',
+  changesGitLens: 'Git',
+  changesSessionLens: '本輪檔案',
+  changesFilterAll: '全部',
+  changesFilterEmpty: '沒有此類操作',
+  changesOpenDiffTab: '在獨立分頁中開啟',
+  changesClosePreview: '關閉預覽',
+  changesResizePreview: '調整預覽高度',
   staged: '已暫存',
   unstaged: '未暫存',
   cancel: '取消',
diff --git a/src/client/locales-zh-MO.ts b/src/client/locales-zh-MO.ts
index 1fc6065..7dcd489 100644
--- a/src/client/locales-zh-MO.ts
+++ b/src/client/locales-zh-MO.ts
@@ -32,18 +32,16 @@
 /** The zh-HK dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const zhMO: Record<string, string> = {
   files: '檔案',
-  fileTrace: '檔案追蹤',
-  fileTraceEmpty: '本工作階段還沒有檔案操作',
-  fileTraceRead: '讀取',
-  fileTraceWrite: '寫入',
-  fileTraceEdit: '編輯',
-  fileTraceRunning: '執行中',
-  fileTraceError: '出錯',
-  fileTraceFold: '{count} 行…點擊展開',
-  fileTraceContext: '上下文',
-  fileTracePriorUnknown: '變更前的內容不在視窗內，顯示為全部新增',
+  changesSessionEmpty: '本工作階段還沒有檔案操作',
+  changesRead: '讀取',
+  changesWrite: '寫入',
+  changesEdit: '編輯',
+  changesRunning: '執行中',
+  changesError: '出錯',
+  changesFold: '{count} 行…點擊展開',
+  changesContext: '上下文',
+  changesPriorUnknown: '變更前的內容不在視窗內，顯示為全部新增',
   explorer: '檔案總管',
-  git: '原始碼管理',
   terminal: '終端',
   editor: '編輯器',
   editorExplorer: '檔案開啟方式',
@@ -153,7 +151,14 @@ export const zhMO: Record<string, string> = {
   worktree: '工作樹',
   checkoutError: '切換分支失敗',
   history: '歷史',
-  changes: '變更',
+  changes: '檔案變動',
+  changesGitLens: 'Git',
+  changesSessionLens: '本輪檔案',
+  changesFilterAll: '全部',
+  changesFilterEmpty: '沒有此類操作',
+  changesOpenDiffTab: '在獨立分頁中開啟',
+  changesClosePreview: '關閉預覽',
+  changesResizePreview: '調整預覽高度',
   staged: '已暫存',
   unstaged: '未暫存',
   cancel: '取消',
diff --git a/src/client/locales-zh-TW.ts b/src/client/locales-zh-TW.ts
index d5846e3..23fa78f 100644
--- a/src/client/locales-zh-TW.ts
+++ b/src/client/locales-zh-TW.ts
@@ -32,18 +32,16 @@
 /** The zh-HK dictionary (key-set-equal to zh, enforced by the type annotation in locales.ts). */
 export const zhTW: Record<string, string> = {
   files: '檔案',
-  fileTrace: '檔案追蹤',
-  fileTraceEmpty: '本作業階段還沒有檔案操作',
-  fileTraceRead: '讀取',
-  fileTraceWrite: '寫入',
-  fileTraceEdit: '編輯',
-  fileTraceRunning: '執行中',
-  fileTraceError: '出錯',
-  fileTraceFold: '{count} 行…點擊展開',
-  fileTraceContext: '上下文',
-  fileTracePriorUnknown: '變更前的內容不在視窗內，顯示為全部新增',
+  changesSessionEmpty: '本作業階段還沒有檔案操作',
+  changesRead: '讀取',
+  changesWrite: '寫入',
+  changesEdit: '編輯',
+  changesRunning: '執行中',
+  changesError: '出錯',
+  changesFold: '{count} 行…點擊展開',
+  changesContext: '上下文',
+  changesPriorUnknown: '變更前的內容不在視窗內，顯示為全部新增',
   explorer: '檔案總管',
-  git: '原始碼管理',
   terminal: '終端',
   editor: '編輯器',
   editorExplorer: '檔案開啟方式',
@@ -153,7 +151,14 @@ export const zhTW: Record<string, string> = {
   worktree: '工作樹',
   checkoutError: '切換分支失敗',
   history: '歷史',
-  changes: '變更',
+  changes: '檔案變動',
+  changesGitLens: 'Git',
+  changesSessionLens: '本輪檔案',
+  changesFilterAll: '全部',
+  changesFilterEmpty: '沒有此類操作',
+  changesOpenDiffTab: '在獨立頁籤中開啟',
+  changesClosePreview: '關閉預覽',
+  changesResizePreview: '調整預覽高度',
   staged: '已暫存',
   unstaged: '未暫存',
   cancel: '取消',
diff --git a/src/client/locales.ts b/src/client/locales.ts
index c1161c9..06a3215 100644
--- a/src/client/locales.ts
+++ b/src/client/locales.ts
@@ -24,18 +24,16 @@
 /** The zh dictionary (also registered into the DSH locale registry under {@link LOCALE_NS}). */
 export const zh = {
   files: '文件',
-  fileTrace: '文件追踪',
-  fileTraceEmpty: '本会话还没有文件操作',
-  fileTraceRead: '读取',
-  fileTraceWrite: '写入',
-  fileTraceEdit: '编辑',
-  fileTraceRunning: '执行中',
-  fileTraceError: '出错',
-  fileTraceFold: '{count} 行…点击展开',
-  fileTraceContext: '上下文',
-  fileTracePriorUnknown: '变更前的内容不在窗口内，显示为全新增',
+  changesSessionEmpty: '本会话还没有文件操作',
+  changesRead: '读取',
+  changesWrite: '写入',
+  changesEdit: '编辑',
+  changesRunning: '执行中',
+  changesError: '出错',
+  changesFold: '{count} 行…点击展开',
+  changesContext: '上下文',
+  changesPriorUnknown: '变更前的内容不在窗口内，显示为全新增',
   explorer: '资源管理器',
-  git: '源代码管理',
   terminal: '终端',
   editor: '编辑器',
   editorExplorer: '文件打开方式',
@@ -144,7 +142,14 @@ export const zh = {
   worktree: '工作树',
   checkoutError: '切换分支失败',
   history: '历史',
-  changes: '变更',
+  changes: '文件变动',
+  changesGitLens: 'Git',
+  changesSessionLens: '本轮文件',
+  changesFilterAll: '全部',
+  changesFilterEmpty: '没有此类操作',
+  changesOpenDiffTab: '在独立页签中打开',
+  changesClosePreview: '关闭预览',
+  changesResizePreview: '调整预览高度',
   staged: '已暂存',
   unstaged: '未暂存',
   cancel: '取消',
@@ -402,18 +407,16 @@ export const zh = {
 /** The en dictionary (key-set-equal to zh, enforced by the type annotation). */
 export const en: Record<keyof typeof zh, string> = {
   files: 'Files',
-  fileTrace: 'File trace',
-  fileTraceEmpty: 'No file operations in this session yet',
-  fileTraceRead: 'Read',
-  fileTraceWrite: 'Write',
-  fileTraceEdit: 'Edit',
-  fileTraceRunning: 'running',
-  fileTraceError: 'error',
-  fileTraceFold: '{count} lines…click to expand',
-  fileTraceContext: 'context',
-  fileTracePriorUnknown: 'Prior content is outside the loaded window; shown as all-added',
+  changesSessionEmpty: 'No file operations in this session yet',
+  changesRead: 'Read',
+  changesWrite: 'Write',
+  changesEdit: 'Edit',
+  changesRunning: 'running',
+  changesError: 'error',
+  changesFold: '{count} lines…click to expand',
+  changesContext: 'context',
+  changesPriorUnknown: 'Prior content is outside the loaded window; shown as all-added',
   explorer: 'Explorer',
-  git: 'Source Control',
   terminal: 'Terminal',
   editor: 'Editor',
   editorExplorer: 'File open behavior',
@@ -523,6 +526,13 @@ export const en: Record<keyof typeof zh, string> = {
   checkoutError: 'Branch switch failed',
   history: 'History',
   changes: 'Changes',
+  changesGitLens: 'Git',
+  changesSessionLens: 'Session',
+  changesFilterAll: 'All',
+  changesFilterEmpty: 'No operations of this kind',
+  changesOpenDiffTab: 'Open in a diff tab',
+  changesClosePreview: 'Close preview',
+  changesResizePreview: 'Resize preview',
   staged: 'Staged',
   unstaged: 'Unstaged',
   cancel: 'Cancel',
diff --git a/src/client/paths.ts b/src/client/paths.ts
index 8fd5490..7712aa1 100644
--- a/src/client/paths.ts
+++ b/src/client/paths.ts
@@ -61,3 +61,12 @@ export function isWithinWorkspace(base: string, target: string): boolean {
   const lt = t.toLowerCase()
   return lt === lb || lt.startsWith(`${lb}/`)
 }
+
+/**
+ * The last path segment of a '/'- or '\'-separated path (a diff tab title,
+ * a worktree label). Returns the whole string when no separator is present.
+ */
+export function baseName(path: string): string {
+  const at = Math.max(path.lastIndexOf('/'), path.lastIndexOf('\\'))
+  return at === -1 ? path : path.slice(at + 1)
+}
diff --git a/src/client/sidebar.module.css b/src/client/sidebar.module.css
index f3b74e3..f509375 100644
--- a/src/client/sidebar.module.css
+++ b/src/client/sidebar.module.css
@@ -2177,141 +2177,9 @@ body[data-dsh-sidebar-dragging] .bottomPanel {
   color: var(--dsw-alias-state-error-primary);
 }
 
-/* ── Git ───────────────────────────────────────────────────────────────── */
-
-.git {
-  flex: 1;
-  min-height: 0;
-  min-width: 0;
-  display: flex;
-  flex-direction: column;
-  overflow-y: auto;
-  /* Tab pages never scroll horizontally: content wraps or truncates to the
-     panel width instead of panning sideways. */
-  overflow-x: hidden;
-}
-
-.gitHeader {
-  flex: none;
-  display: flex;
-  align-items: center;
-  gap: 8px;
-  height: 36px;
-  padding: 0 8px 0 12px;
-}
-
-.gitWorktreeRow {
-  flex: none;
-  display: flex;
-  align-items: center;
-  gap: 8px;
-  padding: 6px 8px 0 12px;
-}
-
-.gitWorktreeLabel {
-  flex: none;
-  color: var(--dsw-alias-label-tertiary);
-  font: var(--dsw-font-xxxs-11);
-}
-
-.gitBranchSelect {
-  flex: 1;
-  min-width: 0;
-  height: 26px;
-  padding: 0 6px;
-  border: 1px solid var(--dsw-alias-border-l2);
-  border-radius: 6px;
-  background: var(--dsw-alias-bg-base);
-  color: var(--dsw-alias-label-primary);
-  font: var(--dsw-font-xxs-12);
-}
-
-.gitSection {
-  border-top: 1px solid var(--dsw-alias-border-l1);
-}
-
-.gitSectionHeader {
-  display: flex;
-  align-items: center;
-  justify-content: space-between;
-  padding: 6px 12px 4px;
-  font: var(--dsw-font-xxxs-strong-11);
-  color: var(--dsw-alias-label-tertiary);
-  text-transform: uppercase;
-}
-
-.gitLink {
-  border: none;
-  background: transparent;
-  font: var(--dsw-font-xxxs-11);
-  color: var(--dsw-alias-brand-primary);
-  cursor: pointer;
-  padding: 0;
-}
-
-.gitLink:hover:not(:disabled) {
-  text-decoration: underline;
-}
-
-.gitLink:disabled {
-  opacity: 0.4;
-  cursor: default;
-}
-
-.gitRow {
-  display: flex;
-  align-items: center;
-  gap: 6px;
-  min-height: 34px;
-  margin: 0 6px;
-  padding: 0 8px;
-  border-radius: 8px;
-  animation: dsh-row-in 150ms var(--ds-ease-in-out);
-}
-
-.gitRow:hover {
-  background: var(--dsw-alias-interactive-bg-hover);
-}
-
-.gitRowSelected {
-  background: var(--dsw-alias-interactive-bg-active);
-}
-
-.gitRowMain {
-  flex: 1;
-  min-width: 0;
-  display: flex;
-  align-items: center;
-  gap: 8px;
-  border: none;
-  background: transparent;
-  padding: 3px 0;
-  cursor: pointer;
-  text-align: left;
-}
-
-.gitBadge {
-  flex: none;
-  width: 20px;
-  height: 16px;
-  display: inline-flex;
-  align-items: center;
-  justify-content: center;
-  border-radius: 4px;
-  font: var(--dsw-font-xxxs-strong-11);
-  background: var(--dsw-alias-interactive-bg-hover);
-  color: var(--dsw-alias-label-secondary);
-}
-
-.gitName {
-  flex: 1;
-  min-width: 0;
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-  font: var(--dsw-font-s-14);
-  color: var(--dsw-alias-label-primary);
-}
+/* ── Diff tab (generic states + shell; the changes tab owns the rest in
+   changes.module.css, and the diff rows themselves live in
+   diff/diff.module.css) ────────────────────────────────────────────────── */
 
 .gitEmpty {
   padding: 4px 12px 8px;
@@ -2333,13 +2201,9 @@ body[data-dsh-sidebar-dragging] .bottomPanel {
   white-space: pre-wrap;
 }
 
-.gitDiff {
-  border-top: 1px solid var(--dsw-alias-border-l1);
-  padding: 8px;
-}
-
-/* The diff tab (a change opened from the git panel, like VSCode's diff
-   editor): header + scrollable diff body, no horizontal panning. */
+/* The diff tab (a change expanded from the changes tab's preview, like
+   VSCode's diff editor): header + scrollable diff body, no horizontal
+   panning; rows render through the shared diff module. */
 .gitDiffTab {
   flex: 1;
   min-height: 0;
@@ -2370,276 +2234,12 @@ body[data-dsh-sidebar-dragging] .bottomPanel {
   color: var(--dsw-alias-label-primary);
 }
 
-/* One changed file's section: path header, hunk headers, aligned lines. */
-.gitDiffFile {
-  width: 100%;
-  display: flex;
-  align-items: baseline;
-  gap: 6px;
-  padding: 8px 2px 2px;
-  border: 0;
-  background: transparent;
-  color: inherit;
-  text-align: left;
-  cursor: pointer;
-}
-
-.gitDiffFile:disabled {
-  cursor: default;
-}
-
-.gitDiffFile:hover:not(:disabled) {
-  background: var(--dsw-alias-interactive-bg-hover);
-}
-
-.gitDiffFileChevron {
-  flex: none;
-  color: var(--dsw-alias-label-tertiary);
-  transform: rotate(0deg);
-}
-
-.gitDiffFileChevronExpanded {
-  transform: rotate(90deg);
-}
-
-.gitDiffFilePath {
-  font: var(--dsw-font-xxs-strong-12);
-  color: var(--dsw-alias-label-primary);
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-}
-
-.gitDiffFileOld {
-  flex: none;
-  font: var(--dsw-font-xxxs-11);
-  color: var(--dsw-alias-label-tertiary);
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-  max-width: 40%;
-}
-
-.gitDiffFileTag {
-  flex: none;
-  padding: 0 6px;
-  border: 1px solid var(--dsw-alias-border-l2);
-  border-radius: 999px;
-  font: var(--dsw-font-xxxs-strong-11);
-  color: var(--dsw-alias-label-secondary);
-}
-
-.gitDiffHunk {
-  display: flex;
-  gap: 8px;
-  padding: 3px 2px;
-  font: var(--dsw-font-markdown-code-block-small);
-  color: var(--dsw-alias-label-tertiary);
-}
-
-.gitDiffHunkHeader {
-  flex: none;
-  color: var(--dsw-alias-label-secondary);
-}
-
-.gitDiffHunkSection {
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-}
-
 /* One aligned diff line: old gutter / new gutter / code. Lines WRAP instead
    of scrolling horizontally (the tab-page rule: fill the width adaptively),
    with the long-token fallback breaking anywhere a space never comes. */
-.gitDiffLine {
-  display: flex;
-  align-items: stretch;
-  font: var(--dsw-font-markdown-code-block-small);
-  line-height: 20px;
-  white-space: pre-wrap;
-  overflow-wrap: anywhere;
-  min-width: 0;
-}
-
-.gitDiffNum {
-  flex: none;
-  width: 36px;
-  padding-right: 8px;
-  text-align: right;
-  color: var(--dsw-alias-label-tertiary);
-  user-select: none;
-}
-
-.gitDiffCode {
-  flex: 1;
-  min-width: 0;
-  overflow: visible;
-}
-
-.gitDiffCtx {
-  color: var(--dsw-alias-label-primary);
-}
-
-.gitDiffDel {
-  color: var(--dsw-alias-state-error-primary);
-  background: color-mix(in srgb, var(--dsw-alias-state-error-primary) 12%, transparent);
-}
-
-.gitDiffAdd {
-  color: var(--dsw-alias-state-success-primary);
-  background: color-mix(in srgb, var(--dsw-alias-state-success-primary) 12%, transparent);
-}
-
-.gitDiffMeta {
-  padding-left: 2px;
-}
-
-.gitDiffMetaText {
-  font: var(--dsw-font-xxxs-11);
-  font-style: italic;
-  color: var(--dsw-alias-label-tertiary);
-}
-
-.gitDiffExpand {
-  display: block;
-  width: 100%;
-  margin: 4px 0;
-  border: none;
-  background: transparent;
-  font: var(--dsw-font-xxs-12);
-  color: var(--dsw-alias-brand-primary);
-  cursor: pointer;
-  text-align: center;
-}
-
-.gitDiffExpand:hover {
-  background: var(--dsw-alias-interactive-bg-hover);
-}
-
-.gitConfirmDesc {
-  margin: 0;
-  font: var(--dsw-font-s-14);
-  color: var(--dsw-alias-label-primary);
-  white-space: pre-wrap;
-}
-
-.gitCommit {
-  display: flex;
-  gap: 6px;
-  padding: 8px 12px;
-  border-top: 1px solid var(--dsw-alias-border-l1);
-  align-items: center;
-}
-
-.gitCommitInput {
-  flex: 1;
-  min-width: 0;
-}
-
-.gitCommitButton {
-  flex: none;
-  height: 26px;
-  padding: 0 12px;
-  border: none;
-  border-radius: 6px;
-  background: var(--dsw-alias-button-primary-fill);
-  color: var(--dsw-alias-label-primary-inverted);
-  font: var(--dsw-font-xxs-strong-12);
-  cursor: pointer;
-}
-
-.gitCommitButton:hover:not(:disabled) {
-  background: var(--dsw-alias-button-primary-hover);
-}
-
-.gitCommitButton:disabled {
-  opacity: 0.45;
-  cursor: default;
-}
 
 /* A history row: line 1 = hash + subject, line 2 = ref badges + author/date
    (badges live on the second line so they never crowd the subject). */
-.gitLogRow {
-  display: flex;
-  flex-direction: column;
-  gap: 2px;
-  padding: 5px 12px;
-  cursor: pointer;
-  border-radius: 8px;
-}
-
-.gitLogRow:hover {
-  background: var(--dsw-alias-interactive-bg-hover);
-}
-
-.gitLogLine1 {
-  display: flex;
-  align-items: baseline;
-  gap: 8px;
-  min-width: 0;
-}
-
-.gitLogHash {
-  flex: none;
-  font: var(--dsw-font-markdown-code-block-small);
-  color: var(--dsw-alias-label-tertiary);
-}
-
-.gitLogLine2 {
-  display: flex;
-  align-items: center;
-  gap: 6px;
-  min-width: 0;
-  flex-wrap: wrap;
-}
-
-.gitLogRef {
-  flex: none;
-  padding: 0 5px;
-  border: 1px solid var(--dsw-alias-border-l2);
-  border-radius: 999px;
-  font: var(--dsw-font-xxxs-strong-11);
-  color: var(--dsw-alias-brand-primary);
-  white-space: nowrap;
-}
-
-.gitLogSubject {
-  flex: 1;
-  min-width: 0;
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-  font: var(--dsw-font-s-14);
-  color: var(--dsw-alias-label-primary);
-}
-
-.gitLogMeta {
-  font: var(--dsw-font-xxxs-11);
-  color: var(--dsw-alias-label-tertiary);
-}
-
-.gitLogMore {
-  display: block;
-  width: calc(100% - 24px);
-  margin: 4px 12px 8px;
-  padding: 6px 0;
-  border: 1px solid var(--dsw-alias-border-l2);
-  border-radius: 6px;
-  background: transparent;
-  font: var(--dsw-font-xxs-12);
-  color: var(--dsw-alias-label-secondary);
-  cursor: pointer;
-}
-
-.gitLogMore:hover:not(:disabled) {
-  background: var(--dsw-alias-interactive-bg-hover);
-  color: var(--dsw-alias-label-primary);
-}
-
-.gitLogMore:disabled {
-  opacity: 0.5;
-  cursor: default;
-}
 
 /* ── Intercepted produced-files row ────────────────────────────────────── */
 
@@ -2700,13 +2300,6 @@ body[data-dsh-sidebar-dragging] .bottomPanel {
 .paneCard:focus-visible,
 .explorerRow:focus-visible,
 .explorerRef:focus-visible,
-.gitRowMain:focus-visible,
-.gitLink:focus-visible,
-.gitCommitButton:focus-visible,
-.gitLogRow:focus-visible,
-.gitLogMore:focus-visible,
-.gitDiffFile:focus-visible,
-.gitDiffExpand:focus-visible,
 .terminalRetry:focus-visible,
 .editorModeButton:focus-visible,
 .editorDownloadLink:focus-visible,
@@ -2728,7 +2321,6 @@ body[data-dsh-sidebar-dragging] .bottomPanel {
   .tabBarPlus,
   .paneCard,
   .explorerRow,
-  .gitRow,
   .divider,
   .dividerRow::after,
   .dividerCol::after {
diff --git a/tests/builtins.spec.ts b/tests/builtins.spec.ts
index 92a795e..4e78ec1 100644
--- a/tests/builtins.spec.ts
+++ b/tests/builtins.spec.ts
@@ -1,10 +1,11 @@
 /**
- * Built-in registration tests: the plugin registers 8 tabs and 6 file
+ * Built-in registration tests: the plugin registers 7 tabs and 6 file
  * viewers through the same service external plugins use (dogfooding);
  * the catch-all `code` viewer, the NUL-sniffing `binary-download` viewer,
  * and the html sandbox settings pin the registry's behavior. (Office
  * previews are NOT built in — they moved to the recommended office plugin,
- * see src/client/plugins-viewers.ts.)
+ * see src/client/plugins-viewers.ts.) The git tab is the unified changes
+ * tab (git lens + session lens, PR #471's file-trace merged in).
  */
 import { describe, expect, it } from 'vitest'
 // First import: browser globals before the xterm-carrying builtin graph loads.
@@ -27,20 +28,20 @@ function setup(options: BuiltinTabOptions = {}): { service: ReturnType<typeof cr
 }
 
 describe('built-in tab registrations', () => {
-  it('registers the 8 built-in tabs', () => {
+  it('registers the 7 built-in tabs', () => {
     const { service } = setup()
     expect(service.getTabs().map(t => t.id).sort()).toEqual(
-      ['browser', 'diff', 'editor', 'file-trace', 'git', 'sidechat', 'subagent', 'terminal'],
+      ['browser', 'diff', 'editor', 'git', 'sidechat', 'subagent', 'terminal'],
     )
   })
 
-  it('the file-trace tab is a single-instance badge-carrying visible tab', () => {
+  it('the git (changes) tab is a single-instance badge-carrying visible tab', () => {
     const { service } = setup()
-    const trace = service.getTab('file-trace')
-    expect(trace?.single).toBe(true)
-    expect(trace?.hidden).not.toBe(true)
-    expect(trace?.badge).toBeDefined()
-    expect(trace?.component).toBeDefined()
+    const changes = service.getTab('git')
+    expect(changes?.single).toBe(true)
+    expect(changes?.hidden).not.toBe(true)
+    expect(changes?.badge).toBeDefined()
+    expect(changes?.component).toBeDefined()
   })
 
   it('only diff is hidden from the + menu; editor is the visible files window (order 10)', () => {
diff --git a/tests/filetrace.spec.ts b/tests/changes-ops.spec.ts
similarity index 93%
rename from tests/filetrace.spec.ts
rename to tests/changes-ops.spec.ts
index 288f752..71bf276 100644
--- a/tests/filetrace.spec.ts
+++ b/tests/changes-ops.spec.ts
@@ -1,12 +1,12 @@
 /**
- * File-trace tab data layer: event-log folding into file operations, plus a
- * sanity pass over the ported diff/highlight engines (their full behavior
- * suites live in the standalone dsh-file-trace plugin).
+ * Changes tab session-lens data layer: event-log folding into file
+ * operations, plus a sanity pass over the shared diff/highlight engines
+ * (their full behavior suites live in the standalone dsh-file-trace plugin).
  */
 import { describe, expect, it } from 'vitest'
-import { extractFileOps, groupByFile, knownContentBefore, parseReadLines } from '../src/client/filetrace/ops.ts'
-import { diffLines, buildDiffSegments, coalesceInline, diffInline } from '../src/client/filetrace/diff.ts'
-import { langOfPath, scanLine } from '../src/client/filetrace/highlight.ts'
+import { extractFileOps, groupByFile, knownContentBefore, parseReadLines } from '../src/client/changes/ops.ts'
+import { diffLines, buildDiffSegments, coalesceInline, diffInline } from '../src/client/diff/rows.ts'
+import { langOfPath, scanLine } from '../src/client/diff/highlight.ts'
 import type { SidebarSessionEvent } from '../src/context-types.ts'
 
 /** One synthetic session event. */
diff --git a/tests/changes-tab.spec.tsx b/tests/changes-tab.spec.tsx
new file mode 100644
index 0000000..d7f876b
--- /dev/null
+++ b/tests/changes-tab.spec.tsx
@@ -0,0 +1,133 @@
+/**
+ * The unified changes tab shell: the lens switcher swaps the Git lens for
+ * the session lens, and a Git-lens file row opens the shared preview pane
+ * (loaded through the mocked git API, rendered by the shared DiffFiles
+ * stack) instead of minting a diff tab directly.
+ */
+// @vitest-environment jsdom
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { createElement } from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { act } from 'react-dom/test-utils'
+import { ChangesTab } from '../src/client/changes/ChangesTab.tsx'
+import { createSidebarStore } from '../src/client/state.ts'
+import { api, type GitStatusResult, type GitWorktree } from '../src/client/api.ts'
+import type { Context } from '../src/context-types.ts'
+import type { SidebarTab } from '../src/client/state.ts'
+
+;(globalThis as Record<string, unknown>).IS_REACT_ACT_ENVIRONMENT = true
+
+const MAIN = 'C:/repo/main'
+
+function fakeContext(): Context {
+  return {
+    sessions: { get: () => undefined },
+    get: () => undefined,
+    on: () => () => { /* no-op */ },
+  } as unknown as Context
+}
+
+function mount(root: Root): void {
+  const tab: SidebarTab = { id: 'git', type: 'git', title: 'Changes' }
+  act(() => {
+    root.render(createElement(ChangesTab, {
+      ctx: fakeContext(),
+      store: createSidebarStore(),
+      scope: { sessionId: 'session', cwd: MAIN },
+      tab,
+      visible: false,
+      onOpenFile: () => {},
+      onOpenDiff: () => {},
+    }))
+  })
+}
+
+function mockGit(entries: Array<{ path: string; xy: string }>): void {
+  vi.spyOn(api, 'gitWorktrees').mockResolvedValue([
+    { path: MAIN, branch: 'main', current: true, changes: entries.length },
+  ] as GitWorktree[])
+  vi.spyOn(api, 'gitStatus').mockResolvedValue({
+    isRepo: true, branch: 'main', entries,
+  } as GitStatusResult)
+  vi.spyOn(api, 'gitBranch').mockResolvedValue({ current: 'main', names: ['main'] })
+  vi.spyOn(api, 'gitLog').mockResolvedValue([])
+}
+
+async function flushEffects(): Promise<void> {
+  await act(async () => { await Promise.resolve() })
+  await act(async () => { await Promise.resolve() })
+}
+
+afterEach(() => {
+  vi.restoreAllMocks()
+  document.body.innerHTML = ''
+})
+
+describe('ChangesTab', () => {
+  it('renders the git lens by default and previews a file row in the pane', async () => {
+    mockGit([{ path: 'src/a.ts', xy: ' M' }])
+    vi.spyOn(api, 'gitDiff').mockResolvedValue({
+      diff: [
+        'diff --git a/src/a.ts b/src/a.ts',
+        '--- a/src/a.ts',
+        '+++ b/src/a.ts',
+        '@@ -1 +1 @@',
+        '-old',
+        '+new',
+      ].join('\n'),
+    })
+
+    const container = document.createElement('div')
+    document.body.append(container)
+    const root: Root = createRoot(container)
+    try {
+      mount(root)
+      await flushEffects()
+
+      // Git lens: the file row from the mocked status (badge letter + path).
+      const row = [...container.querySelectorAll<HTMLButtonElement>('button')]
+        .find(button => button.textContent?.includes('src/a.ts'))
+      expect(row).toBeDefined()
+
+      // Clicking the row previews inline (no diff tab minted): the shared
+      // renderer draws the added row.
+      await act(async () => { row!.click() })
+      await flushEffects()
+      expect(container.textContent).toContain('new')
+
+      // The preview survives a lens switch (it is a dock, not lens state).
+      const group = container.querySelector('[role="group"]')
+      const sessionButton = [...group!.querySelectorAll<HTMLButtonElement>('button')]
+        .find(button => button.getAttribute('aria-pressed') === 'false')
+      expect(sessionButton).toBeDefined()
+      await act(async () => { sessionButton!.click() })
+      expect(container.textContent).toContain('src/a.ts')
+    } finally {
+      act(() => { root.unmount() })
+      container.remove()
+    }
+  })
+
+  it('switches to the session lens, which shows its empty state without ops', async () => {
+    mockGit([])
+    const container = document.createElement('div')
+    document.body.append(container)
+    const root: Root = createRoot(container)
+    try {
+      mount(root)
+      await flushEffects()
+      const group = container.querySelector('[role="group"]')
+      expect(group).not.toBeNull()
+      const buttons = [...group!.querySelectorAll<HTMLButtonElement>('button')]
+      await act(async () => { buttons[1]!.click() })
+      // No session events in the fake context: the session lens empty state
+      // (locale-agnostic — the test env may resolve zh or en).
+      expect(container.textContent).toMatch(/本会话还没有文件操作|No file operations/)
+      // The git lens (its branch picker) is unmounted by the switch.
+      expect(container.querySelector('select')).toBeNull()
+    } finally {
+      act(() => { root.unmount() })
+      container.remove()
+    }
+  })
+})
diff --git a/tests/diff-view-collapse.spec.tsx b/tests/diff-files-collapse.spec.tsx
similarity index 91%
rename from tests/diff-view-collapse.spec.tsx
rename to tests/diff-files-collapse.spec.tsx
index d6785e5..ce0627e 100644
--- a/tests/diff-view-collapse.spec.tsx
+++ b/tests/diff-files-collapse.spec.tsx
@@ -3,7 +3,7 @@ import { afterEach, describe, expect, it } from 'vitest'
 import { createElement } from 'react'
 import { createRoot, type Root } from 'react-dom/client'
 import { act } from 'react-dom/test-utils'
-import { DiffView } from '../src/client/DiffView.tsx'
+import { DiffFiles } from '../src/client/diff/DiffFiles.tsx'
 
 ;(globalThis as Record<string, unknown>).IS_REACT_ACT_ENVIRONMENT = true
 
@@ -30,13 +30,13 @@ const diff = [
 
 afterEach(() => { document.body.innerHTML = '' })
 
-describe('DiffView file folding', () => {
+describe('DiffFiles file folding', () => {
   it('expands source by default while tests and docs stay collapsed', () => {
     const container = document.createElement('div')
     document.body.append(container)
     const root: Root = createRoot(container)
     try {
-      act(() => { root.render(createElement(DiffView, { diff })) })
+      act(() => { root.render(createElement(DiffFiles, { diff })) })
       const headers = [...container.querySelectorAll<HTMLButtonElement>('button[aria-expanded]')]
       expect(headers).toHaveLength(3)
       expect(headers.map(header => header.getAttribute('aria-expanded'))).toEqual(['true', 'false', 'false'])
diff --git a/tests/diff-rows.spec.ts b/tests/diff-rows.spec.ts
new file mode 100644
index 0000000..47d7620
--- /dev/null
+++ b/tests/diff-rows.spec.ts
@@ -0,0 +1,123 @@
+/**
+ * The unified-diff adapter: git's own hunks (from parseUnifiedDiff) convert
+ * into the shared DiffRow segments — rewrite pairing applies inside git
+ * hunks exactly like session-op diffs, the unemitted context gaps between
+ * hunks become non-expandable folds carrying their line ranges, and the
+ * header stats (+n −m) count mods on both sides.
+ */
+import { describe, expect, it } from 'vitest'
+import { parseUnifiedDiff, unifiedSegments, diffLines, pairMods, diffStats, untrackedFile } from '../src/client/diff/rows.ts'
+
+const twoHunks = [
+  'diff --git a/a.ts b/a.ts',
+  '--- a/a.ts',
+  '+++ b/a.ts',
+  '@@ -1,4 +1,4 @@',
+  ' context',
+  '-old line',
+  '+new line',
+  ' tail',
+  '@@ -20,3 +20,4 @@',
+  ' far below',
+  '-gone',
+  '+kept',
+  '+added',
+  ' tail2',
+].join('\n')
+
+describe('unifiedSegments', () => {
+  it('converts hunk lines to rows and pairs the rewrite as mod', () => {
+    const file = parseUnifiedDiff(twoHunks).files[0]!
+    const segments = unifiedSegments(file)
+    // hunk, gap fold (lines 4..19 hidden), hunk
+    expect(segments.map(s => s.kind)).toEqual(['hunk', 'fold', 'hunk'])
+    const first = segments[0]!
+    expect(first.kind === 'hunk' && first.rows.map(r => r.kind)).toEqual(['context', 'mod', 'mod', 'context'])
+    // The paired rows keep their own side's line number.
+    const modOld = first.kind === 'hunk' ? first.rows[1]! : undefined
+    const modNew = first.kind === 'hunk' ? first.rows[2]! : undefined
+    expect(modOld?.oldLine).toBe(2)
+    expect(modOld?.newLine).toBeUndefined()
+    expect(modNew?.oldLine).toBeUndefined()
+    expect(modNew?.newLine).toBe(2)
+  })
+
+  it('emits a non-expandable fold for the unemitted gap between hunks', () => {
+    const file = parseUnifiedDiff(twoHunks).files[0]!
+    const gap = unifiedSegments(file)[1]!
+    expect(gap.kind).toBe('fold')
+    if (gap.kind === 'fold') {
+      expect(gap.rows).toBeUndefined()
+      // First hunk ends at line 3 on both sides, second starts at 20 → gap 16.
+      expect(gap.count).toBe(16)
+      expect(gap.oldStart).toBe(4)
+      expect(gap.oldEnd).toBe(19)
+      expect(gap.newStart).toBe(4)
+      expect(gap.newEnd).toBe(19)
+    }
+  })
+
+  it('emits a leading fold when the first hunk starts below line 1', () => {
+    const diff = [
+      'diff --git a/a.ts b/a.ts',
+      '--- a/a.ts',
+      '+++ b/a.ts',
+      '@@ -10 +10 @@',
+      '-old',
+      '+new',
+    ].join('\n')
+    const file = parseUnifiedDiff(diff).files[0]!
+    const segments = unifiedSegments(file)
+    expect(segments.map(s => s.kind)).toEqual(['fold', 'hunk'])
+    const lead = segments[0]!
+    if (lead.kind === 'fold') {
+      expect(lead.count).toBe(9)
+      expect(lead.rows).toBeUndefined()
+    }
+  })
+
+  it('carries the no-newline marker as a meta row', () => {
+    const diff = [
+      'diff --git a/a.ts b/a.ts',
+      '--- a/a.ts',
+      '+++ b/a.ts',
+      '@@ -1 +1 @@',
+      '-old',
+      '\\ No newline at end of file',
+      '+new',
+    ].join('\n')
+    const file = parseUnifiedDiff(diff).files[0]!
+    const rows = unifiedSegments(file).flatMap(s => (s.kind === 'hunk' ? s.rows : []))
+    expect(rows.map(r => r.kind)).toEqual(['del', 'meta', 'add'])
+    expect(rows[1]).toMatchObject({ kind: 'meta', text: ' No newline at end of file' })
+  })
+
+  it('counts header stats with mods on both sides', () => {
+    const file = parseUnifiedDiff(twoHunks).files[0]!
+    // Hunk 1 pairs 1 del + 1 add (2 mod rows); hunk 2 pairs 1 of its 1 del
+    // with 1 of its 2 adds (2 mod rows) leaving 1 pure add: 5 added, 4 deleted.
+    expect(diffStats(unifiedSegments(file))).toEqual({ added: 5, deleted: 4 })
+    // A full-file addition (untracked fallback) counts every row once.
+    const untracked = untrackedFile('new.ts', 'a\nb\n')
+    expect(diffStats(unifiedSegments(untracked))).toEqual({ added: 2, deleted: 0 })
+  })
+})
+
+describe('pairMods', () => {
+  it('pairs only the overlapping del/add rows within one run', () => {
+    const rows = pairMods([
+      { kind: 'context' as const, oldLine: 1, newLine: 1, text: 'x' },
+      { kind: 'del' as const, oldLine: 2, text: 'a' },
+      { kind: 'del' as const, oldLine: 3, text: 'b' },
+      { kind: 'add' as const, newLine: 2, text: 'B' },
+      { kind: 'add' as const, newLine: 3, text: 'c' },
+      { kind: 'add' as const, newLine: 4, text: 'd' },
+    ])
+    expect(rows.map(r => r.kind)).toEqual(['context', 'mod', 'mod', 'mod', 'mod', 'add'])
+  })
+
+  it('matches diffLines output (the LCS walk pairs rewrites the same way)', () => {
+    const rows = diffLines('hello world', 'hello dsh')
+    expect(rows.map(r => r.kind)).toEqual(['mod', 'mod'])
+  })
+})
diff --git a/tests/e2e/mount.e2e.ts b/tests/e2e/mount.e2e.ts
index 25ad5ce..f9d16f0 100644
--- a/tests/e2e/mount.e2e.ts
+++ b/tests/e2e/mount.e2e.ts
@@ -14,7 +14,7 @@
  *  3. asserts the plugin's crash markers never appear (no RenderBoundary /
  *     fail() strips, no `pageerror`, no plugin-prefixed console errors);
  *  4. expands the collapsed panel (openByDefault defaults off), sweeps every
- *     built-in tab (Files / Source Control / Tasks / Terminal / Browser) —
+ *     built-in tab (Files / Changes / Tasks / Terminal / Browser) —
  *     including the lazily-fetched terminal chunk — and then opens seeded
  *     files through the Files window's tree (separate mode: each file opens
  *     its own new tab, the seeded home "Files" tab stays the explorer),
@@ -57,7 +57,7 @@ const SEEDED_README_FILE = 'readme-style.md'
 const CRASH_STRIP_PATTERNS = [/^dsh-better-sidebar:/, /^\[dsh-better-sidebar\]/]
 
 /** Built-in tab titles the sweep drives (en-US copy; follows DSH locale). */
-const BUILTIN_TABS = ['Files', 'Source Control', 'Tasks', 'Side Chat (beta)', 'Terminal', 'Browser']
+const BUILTIN_TABS = ['Files', 'Changes', 'Tasks', 'Side Chat (beta)', 'Terminal', 'Browser']
 
 let api: APIRequestContext
 /** The seeded session id (captured by seedSession; the Side Chat smoke's parent). */
diff --git a/tests/git-view-worktree.spec.tsx b/tests/git-view-worktree.spec.tsx
index e4b6e2a..b399f42 100644
--- a/tests/git-view-worktree.spec.tsx
+++ b/tests/git-view-worktree.spec.tsx
@@ -9,7 +9,7 @@ import { afterEach, describe, expect, it, vi } from 'vitest'
 import { createElement } from 'react'
 import { createRoot, type Root } from 'react-dom/client'
 import { act } from 'react-dom/test-utils'
-import { GitView } from '../src/client/GitView.tsx'
+import { GitLens } from '../src/client/changes/GitLens.tsx'
 import { createSidebarStore } from '../src/client/state.ts'
 import { api, type GitLogEntry, type GitStatusResult, type GitWorktree } from '../src/client/api.ts'
 
@@ -56,7 +56,7 @@ async function flushEffects(): Promise<void> {
 
 afterEach(() => { vi.restoreAllMocks() })
 
-describe('GitView linked-worktree consistency', () => {
+describe('GitLens (changes tab, git lens) linked-worktree consistency', () => {
   it('refreshes status, branches and history together on auto and manual selection', async () => {
     vi.spyOn(api, 'gitWorktrees').mockResolvedValue(inventories)
     vi.spyOn(api, 'gitStatus').mockImplementation(async (_scope, target) => statusFor(target))
@@ -71,11 +71,12 @@ describe('GitView linked-worktree consistency', () => {
     const root: Root = createRoot(container)
     try {
       await act(async () => {
-        root.render(createElement(GitView, {
+        root.render(createElement(GitLens, {
           scope: { sessionId: 'session', cwd: MAIN },
           store: createSidebarStore(),
           onOpenFile: () => {},
-          onOpenDiff: () => {},
+          onPreview: () => {},
+          selectedRef: null,
           visible: false,
         }))
       })
@@ -129,11 +130,12 @@ describe('GitView linked-worktree consistency', () => {
     const root: Root = createRoot(container)
     try {
       await act(async () => {
-        root.render(createElement(GitView, {
+        root.render(createElement(GitLens, {
           scope: { sessionId: 'session', cwd: MAIN },
           store: createSidebarStore(),
           onOpenFile: () => {},
-          onOpenDiff: () => {},
+          onPreview: () => {},
+          selectedRef: null,
           visible: false,
         }))
       })
diff --git a/tests/git.spec.ts b/tests/git.spec.ts
index 6d7059e..9932d23 100644
--- a/tests/git.spec.ts
+++ b/tests/git.spec.ts
@@ -5,7 +5,7 @@ import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { promisify } from 'node:util'
 import { describe, expect, it } from 'vitest'
-import { parseUnifiedDiff } from '../src/client/DiffView.tsx'
+import { parseUnifiedDiff } from '../src/client/diff/rows.ts'
 import { parseLogLines, parsePorcelainZ, repoRoots, status } from '../src/git.ts'
 
 const execFileAsync = promisify(execFile)
diff --git a/tests/locales.spec.ts b/tests/locales.spec.ts
index fcfad45..4e12ffe 100644
--- a/tests/locales.spec.ts
+++ b/tests/locales.spec.ts
@@ -61,13 +61,13 @@ describe('locales (DSH i18n following)', () => {
     attachLocale(locale)
 
     locale.switchTo('zh')
-    expect(t('git')).toBe('源代码管理')
+    expect(t('changes')).toBe('文件变动')
     expect(isZh()).toBe(true)
 
     // Live switch: the service's active locale wins even though the
     // browser still asks for en-US.
     locale.switchTo('en')
-    expect(t('git')).toBe('Source Control')
+    expect(t('changes')).toBe('Changes')
     expect(isZh()).toBe(false)
   })
 
@@ -172,8 +172,8 @@ describe('locales (better-locale override)', () => {
     betterLocale.active = 'ja'
     attachBetterLocale(betterLocale)
 
-    // 'git' has no ja entry in this fake; should fall back to the en text.
-    expect(t('git')).toBe('Source Control')
+    // 'changes' has no ja entry in this fake; should fall back to the en text.
+    expect(t('changes')).toBe('Changes')
   })
 
   it('falls back to the zh/en chain when no override is active', () => {