feat: 新增第 8 个内置 tab「文件追踪」——移植 dsh-file-trace 插件

- 数据层：直接折叠会话事件日志(tool/call + tool/result 对)提取文件操作，
  与仓库「读事件日志而非动注册表」的取向一致；含错误文本捕获与
  running 态实时更新(ctx.on('session/event')，不可见时暂停、恢复时追平)
- 视图：操作列表 + 底部可拖拽 diff 面板；行级 diff(删红/增绿/改蓝)+
  行内字符级高亮；读取视图带真实行号；失败操作统一展示真实错误文本
- 语法着色：轻量分词器(关键字/字符串/数字/类型/函数/注释/预处理)，
  色相经 color-mix 落在 diff 三色之间的空档；跨行块注释状态按行序推导
- 单实例 tab，+ 菜单 order 55，角标显示操作数；设置页可整体关闭
  (与独立维护的 dsh-file-trace 插件共存)
- i18n：10 个新 key 同步全部 21 个词典；builtins 测试 7→8；
  README/指南内置清单同步

README_EN.md

@@ -55,7 +55,7 @@
 - **⚡ On-demand Loading**: only ~325KB core at startup; heavy deps (terminal / editor / mermaid diagrams) load on demand ([design](docs/plans/2026-08-12-lazy-chunks-design.md))
 - **🌏 i18n**: UI text follows DSH's language (zh / en) with live switching; with the optional `@huanlin/dsh-plugin-better-locale` peer, 19 third-language overlays (ja / de / fr / …) are available
 
-> 🔌 **Core principle**: service-first — the 7 built-in tabs + 6 viewers register through the same `ctx.betterSidebar` API as third-party plugins, with fully equal capabilities; anything the ecosystem can provide better is delegated to ecosystem plugins (**28+ ecosystem plugins** already — see "🌐 Plugin Ecosystem" below). See "🔌 Service API" and the [external plugin guide](./docs/external-plugin-guide.md).
+> 🔌 **Core principle**: service-first — the 8 built-in tabs + 6 viewers register through the same `ctx.betterSidebar` API as third-party plugins, with fully equal capabilities; anything the ecosystem can provide better is delegated to ecosystem plugins (**28+ ecosystem plugins** already — see "🌐 Plugin Ecosystem" below). See "🔌 Service API" and the [external plugin guide](./docs/external-plugin-guide.md).
 
 ## 🚀 Installation
 
@@ -163,11 +163,12 @@ Update: `git pull && pnpm install && pnpm build` → `node scripts/package-regis
 | **💻 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> |
 | **🌐 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
 
-The `ctx.betterSidebar` service opens two extension points to every plugin: **`registerTab` (sidebar pages)** and **`registerFileViewer` (file previewers)**. The 7 built-in tabs + 6 viewers register through the exact same API — fully equal capabilities.
+The `ctx.betterSidebar` service opens two extension points to every plugin: **`registerTab` (sidebar pages)** and **`registerFileViewer` (file previewers)**. The 8 built-in tabs + 6 viewers register through the exact same API — fully equal capabilities.
 
 ```ts
 import type {} from 'dsh-better-sidebar'  // triggers the ctx.betterSidebar type merge
@@ -445,7 +446,7 @@ All changes since v0.14.0:
 
 ## 🔌 Service API
 
-Since v0.4.0 the plugin exposes the `ctx.betterSidebar` service — other plugins can register sidebar pages and file viewers (the 7 built-in tabs + 6 viewers register through the same service). v0.12.1 completed the base capabilities (complete type exports, capability detection, state subscription, tab badges, lifecycle callbacks, targeted open, plugin-owned settings, etc.).
+Since v0.4.0 the plugin exposes the `ctx.betterSidebar` service — other plugins can register sidebar pages and file viewers (the 8 built-in tabs + 6 viewers register through the same service). v0.12.1 completed the base capabilities (complete type exports, capability detection, state subscription, tab badges, lifecycle callbacks, targeted open, plugin-owned settings, etc.).
 
 Full integration docs (complete fields, matching algorithm, HMR pitfalls, declarative settings, version detection, float windows and the skinning contract): **[`docs/external-plugin-guide.md`](./docs/external-plugin-guide.md)**; repository rules (hard constraints / CI / release) live in [`AGENTS.md`](./AGENTS.md).