feat: 内容型打开自动展开承载面板（宽视口）

宽视口下 openTab 带 path/url seed 时，承载落点 pane 的面板折叠则自动展开：
落点在底部树展开底部面板，否则展开右侧面板；去重聚焦既有 tab 同样展开
（打开必须落在视野内）。窄视口抽屉逻辑不变；类型型打开（+ 菜单、agent
终端自动补 tab）不展开。同步 AGENTS.md / README 文档与测试。

AGENTS.md

@@ -364,6 +364,9 @@ interface BetterSidebarService {
    * url 可选：落地后把 tab 的 path 预填为 URL（侧边栏浏览器导航种子，
    * 通常配合 hostname title；对 createTab 铸造的 tab 同样生效）。
    * 被设置禁用的类型是 no-op（console.warn 提示）。
+   * 内容型打开（带 path/url seed）必须落在视野内：承载落点 pane 的面板
+   * 折叠时自动展开（右侧面板；落点 pane 在底部树则展开底部面板；窄视口
+   * 展开合并抽屉）；类型型打开（+ 菜单、agent 终端自动补 tab）不展开。
    */
   openTab(seed: { type: string; title?: string; path?: string; diff?: SidebarTab['diff']; id?: string; url?: string }): void
   /** 关闭一个 tab */

README.md

@@ -9,14 +9,14 @@
 - **🗂️ 资源管理器**：懒加载目录树（根 = 会话 cwd）、点击在侧边栏打开、行尾 `@文件` 引用到输入框、右键复制路径
 - **📝 编辑与预览**：CodeMirror 6 多语言高亮 + Ctrl/Cmd+S 原子保存；图片 / Markdown（预览/编辑切换）/ HTML（沙箱 iframe 预览，相对资源可加载）/ PDF / Word / Excel / PPT 内联预览，切换 Tab 不丢草稿
 - **⚡ 客户端懒加载**：Office / 终端 / 代码编辑器等重依赖按需分块加载——启动只拉 ~325KB 核心，打开 .xlsx 才拉 Univer（~20MB）、打开 .docx 只拉 docx 预览器、打开终端才拉 xterm；首次打开短暂 loading 后即用（详见 `docs/plans/2026-08-12-lazy-chunks-design.md`）
-- **🌐 浏览器**：内嵌网页浏览 tab（多开），后退/前进/刷新 +「在浏览器中打开」；页面在**沙箱 iframe** 中运行（不透明源：无法访问界面数据与本地文件，拒绝 localhost 等本机地址），界面实时显示沙箱状态、可临时解锁（关闭时红色警示）；被站点拒绝嵌入（X-Frame-Options）时显示原因面板；聊天/界面里的 http(s) 外链默认在侧边栏打开
+- **🌐 浏览器**：内嵌网页浏览 tab（多开），后退/前进/刷新 +「在浏览器中打开」；页面在**沙箱 iframe** 中运行（不透明源：无法访问界面数据与本地文件，拒绝 localhost 等本机地址），界面实时显示沙箱状态、可临时解锁（关闭时红色警示）；被站点拒绝嵌入（X-Frame-Options）时显示原因面板；聊天/界面里的 http(s) 外链默认在侧边栏打开（侧边栏折叠时自动展开面板）
 - **💻 终端**：xterm.js + node-pty 真实 shell（每会话 3 个 UI 上限）、Tab 保活重连回放；可选为模型注入 8 个 `terminal_*` 工具
 - **🌿 Git 面板**：真 diff + VSCode 式 diff tab、懒加载历史、右键暂存/放弃/提交/还原/捡取
 - **🧩 Subagent 页面**：主会话完整 agent 拓扑、点击直达执行记录、实时工具调用轮询、新子代理自动展开
 - **🪟 底部面板**：独立的第二个工作台（与右侧栏同类的标签页），只挤占中间 Agent 输出区、不覆盖左右侧边栏；**首次展开自动开一个新终端**（终端卡片二级设置可关）；右上角 x 一键折叠
 - **📱 移动端**：视口 < 768px（真正的移动端宽度，不对齐宿主 1024 断点）时只显示右侧栏——进入窄屏时底部面板的标签页**直接并入右侧栏标签条**，右上角只剩一枚开关，面板为全宽抽屉；新会话默认收起，聊天里点文件/外链自动展开，不挤压对话区
 - **🔧 分栏工作台**：拖 Tab 拆分/合并分栏（可**跨面板拖 Tab**）、分隔线调比例；右上角持久按钮簇（底栏 + 侧拉 glyph）折叠/展开两个面板；两面板共享拐角双向拖动调节尺寸，拖动 rAF 直写 DOM 保持流畅
-- **🔁 会话隔离**：布局/分栏/Tab/两面板状态按会话持久化（localStorage），陈旧状态自动净化；聊天「产出文件」改在侧边栏打开
+- **🔁 会话隔离**：布局/分栏/Tab/两面板状态按会话持久化（localStorage），陈旧状态自动净化；聊天「产出文件」改在侧边栏打开（面板折叠时自动展开）
 - **⚙️ 声明式设置**：设置页「侧边卡片」分区按注册表渲染功能清单（小卡片网格，高亮 = 启用），每项可独立开/关；二级设置（子代理自动展开、终端工具、底部面板首展自动开终端、沙箱开关等）经齿轮按钮在原生弹窗中编辑
 - **🔌 服务化**：暴露 `ctx.betterSidebar` 服务，其他插件可注册侧边栏 tab 与文件预览器（内置 7 tab + 9 viewer 也走同一服务，详见 [AGENTS.md](./AGENTS.md)）
 

src/client/service.ts

@@ -22,7 +22,7 @@
 import type { ReactNode } from 'react'
 import type { Context } from '../context-types.ts'
 import {
-  activateTab, allLeaves, closeTab as closeTabReducer, openTabInActivePane, patchTab, togglePanel,
+  activateTab, allLeaves, closeTab as closeTabReducer, openTabInActivePane, patchTab, togglePanel, treeOf,
   type SidebarState, type SidebarStore, type SidebarTab,
 } from './state.ts'
 import { isNarrowWidth } from './breakpoints.ts'
@@ -199,6 +199,13 @@ export interface BetterSidebarService {
    * pre-set to the URL (the browser tab's navigation seed; the caller
    * usually pairs it with a hostname `title`). A disabled tab type is a
    * no-op.
+   *
+   * A CONTENT open (a `path` or `url` seed) must land in sight: when the
+   * panel hosting the landing pane is collapsed, it is expanded
+   * automatically (the right panel by default, the bottom panel when the
+   * active pane lives there; on narrow viewports the merged drawer opens).
+   * Type-only opens (the + menu, agent-terminal auto-tabs) never expand —
+   * the panel behavior is their caller's business.
    */
   openTab(seed: { type: string; title?: string; path?: string; diff?: SidebarTab['diff']; id?: string; url?: string }): void
   /** Close a tab by id. */
@@ -345,18 +352,30 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
       } else {
         landed = next
       }
-      // Narrow-viewport drawer: a CONTENT open (file / browser) must be
-      // visible — expand the collapsed drawer so the open lands in sight.
-      // Type-only opens (+ menu, agent-terminal auto-tabs) never expand; on
-      // wide viewports nothing here changes (the panel behavior is the
-      // caller's business).
+      // A CONTENT open (file / browser) must land in sight: when the panel
+      // hosting the landing pane is collapsed, expand it. On narrow
+      // viewports the two workbenches merge into one drawer, so the drawer
+      // (panelOpen) is the only lever; on wide viewports the landing pane's
+      // own panel opens — the bottom panel when the active pane lives in the
+      // bottom tree, else the right panel. Type-only opens (+ menu,
+      // agent-terminal auto-tabs) never expand (the panel behavior is their
+      // caller's business). The check runs on the post-dedupe state, so a
+      // content open that merely FOCUSES an existing tab expands the panel
+      // too — the open must never land out of sight.
       if (
         typeof window !== 'undefined'
-        && isNarrowWidth(window.innerWidth)
         && (seed.path !== undefined || seed.url !== undefined)
-        && !landed.panelOpen
       ) {
-        return togglePanel(landed)
+        if (isNarrowWidth(window.innerWidth)) {
+          if (!landed.panelOpen) return togglePanel(landed)
+        } else {
+          const hostKey = treeOf(landed, landed.activePane ?? '')
+          if (hostKey === 'bottomSplits') {
+            if (!landed.bottomOpen) return { ...landed, bottomOpen: true }
+          } else if (!landed.panelOpen) {
+            return togglePanel(landed)
+          }
+        }
       }
       return landed
     })

tests/service.spec.ts

@@ -466,11 +466,15 @@ describe('service.openTab across the two panels', () => {
   })
 })
 
-describe('service.openTab narrow-viewport auto-expand', () => {
+describe('service.openTab auto-expand for content opens', () => {
   /** The window stub is a plain object (see the file header), so the width is writable. */
   const setWidth = (width: number): void => {
     ;(g.window as { innerWidth: number }).innerWidth = width
   }
+  /** Collapse the right panel (the store defaults it open). */
+  const collapseRightPanel = (store: ReturnType<typeof createSidebarStore>): void => {
+    store.reduce(s => ({ ...s, panelOpen: false }))
+  }
 
   it('expands the collapsed drawer for a path (file) open on a narrow viewport', () => {
     setWidth(390)
@@ -517,13 +521,50 @@ describe('service.openTab narrow-viewport auto-expand', () => {
     }
   })
 
-  it('never expands on a wide viewport (path open keeps the caller’s choice)', () => {
+  it('expands the collapsed right panel for a path (file) open on a wide viewport', () => {
     const store = createSidebarStore()
     const service = createBetterSidebarService(store)
     service.registerTab({ id: 'editor', title: 'Editor', component: () => null })
     store.setSession('s1')
-    store.reduce(s => ({ ...s, panelOpen: false }))
+    collapseRightPanel(store)
     service.openTab({ type: 'editor', title: 'main.ts', path: '/p/main.ts' })
+    const state = store.getSnapshot().state!
+    expect(state.panelOpen).toBe(true)
+    expect(allLeaves(state.splits).flatMap(l => l.tabs).some(t => t.type === 'editor')).toBe(true)
+  })
+
+  it('expands the collapsed right panel for a URL (browser) open on a wide viewport', () => {
+    const store = createSidebarStore()
+    const service = createBetterSidebarService(store)
+    service.registerTab({ id: 'browser', title: 'Browser', component: () => null })
+    store.setSession('s1')
+    collapseRightPanel(store)
+    service.openTab({ type: 'browser', url: 'https://example.com', title: 'example.com' })
+    expect(store.getSnapshot().state!.panelOpen).toBe(true)
+  })
+
+  it('a wide-viewport path open landing in the bottom tree expands the bottom panel instead', () => {
+    const store = createSidebarStore()
+    const service = createBetterSidebarService(store)
+    service.registerTab({ id: 'editor', title: 'Editor', component: () => null })
+    store.setSession('s1')
+    // The last-touched pane lives in the bottom tree and BOTH panels are
+    // collapsed: the open must surface the bottom panel, not the right one.
+    store.reduce(s => ({ ...s, activePane: (s.bottomSplits as { id: string }).id, panelOpen: false, bottomOpen: false }))
+    service.openTab({ type: 'editor', title: 'main.ts', path: '/p/main.ts' })
+    const state = store.getSnapshot().state!
+    expect(state.bottomOpen).toBe(true)
+    expect(state.panelOpen).toBe(false)
+    expect(allLeaves(state.bottomSplits).flatMap(l => l.tabs).some(t => t.type === 'editor')).toBe(true)
+  })
+
+  it('keeps a collapsed panel for a type-only open on a wide viewport', () => {
+    const store = createSidebarStore()
+    const service = createBetterSidebarService(store)
+    service.registerTab({ id: 'explorer', title: 'Explorer', component: () => null })
+    store.setSession('s1')
+    collapseRightPanel(store)
+    service.openTab({ type: 'explorer', title: 'Explorer' })
     expect(store.getSnapshot().state?.panelOpen).toBe(false)
   })
 
@@ -542,4 +583,17 @@ describe('service.openTab narrow-viewport auto-expand', () => {
       setWidth(1024)
     }
   })
+
+  it('expands on a wide viewport even when the open focuses an existing tab (id dedupe)', () => {
+    const store = createSidebarStore()
+    const service = createBetterSidebarService(store)
+    service.registerTab({ id: 'editor', title: 'Editor', component: () => null })
+    store.setSession('s1')
+    service.openTab({ type: 'editor', title: 'main.ts', path: '/p/main.ts' })
+    collapseRightPanel(store)
+    service.openTab({ type: 'editor', title: 'main.ts', path: '/p/main.ts' })
+    const state = store.getSnapshot().state!
+    expect(state.panelOpen).toBe(true)
+    expect(allLeaves(state.splits).flatMap(l => l.tabs).filter(t => t.type === 'editor')).toHaveLength(1)
+  })
 })