Add the workspace task-page container with pin and project aggregation (U6)

Why: U6 brings generated pages into the work view - a compact
task-page section renders the latest conversation surface under the
current-task card (SurfaceView), a pin freezes the shown page against
new arrivals (unpin follows latest), a jump button opens the full
preview, and the project-level aggregate loads on conversation open
for cross-session visibility; when the plugin is disabled or no pages
exist the section disappears and the work view is untouched.

Evidence: tsc clean; vitest 101/101 including the pin/follow test;
knip unchanged.

Impact: Frontend-only; consumes the U6 backend aggregate endpoint.

Refs: proposal r2 U6; Backend #163; Dev task feature/generative-ui-u6

src/api.ts

@@ -33,6 +33,7 @@ export const api = {
   surfaceList: (convId: string) => auth.fetch(`${BASE}/api/conversations/${convId}/surfaces`).then(r => json<any[]>(r)),
   submitSurfaceAction: (id: string, body: { actionId: string; revision: number; requestId: string; data: Record<string, unknown> }) =>
     auth.fetch(`${BASE}/api/surfaces/${id}/actions`, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) }).then(r => json<any>(r)),
+  projectSurfaces: (projectId: string) => auth.fetch(`${BASE}/api/projects/${projectId}/surfaces`).then(r => json<any[]>(r)),
   surfaceGet: (id: string) => auth.fetch(`${BASE}/api/surfaces/${id}`).then(r => json<any>(r)),
   me: () => auth.fetch(`${BASE}/api/me`).then(r => json<{ owner: string; name: string; auth: boolean; authVia?: string; isAdmin?: boolean; mustChangePassword?: boolean }>(r)),
   // ---- 认证与会话（管理员发放制，R2）----

src/components/Workbench.tsx

@@ -4,7 +4,7 @@
 import { store, useStore } from '../store'
 import type { Run } from '../contracts'
 import { InboxList, pendingCount, type ActivityCard, type DocBridge, type InboxFilter } from '@ui'
-import { Icon } from '@ui'
+import { Icon, SurfaceView } from '@ui'
 import { previewTabsKey } from '../previewtabs'
 import { ArtifactsPanel } from './ArtifactsPanel'
 import { PreviewPane } from './PreviewPane'
@@ -115,6 +115,7 @@ function WorkTab({ plan, todos, filter, inboxScope, projectCards, cards }: {
         {inboxScope === 'project'
           ? <ProjectInbox cards={projectCards} filter={filter} />
           : <InboxList cards={cards} docBridge={docBridge} callbacks={inboxCallbacks} filter={filter} />}
+        <WorkspaceSurfaces />
       </div>
     </>
   )
@@ -172,3 +173,33 @@ export function AgentRow({ run, depth }: { run: Run; depth: number }) {
     </div>
   )
 }
+
+// U6 工作区任务页容器：会话内页面在"工作"入口的常驻紧凑视图——默认显示最新
+// 一页，固定（pin）后不随新页面抢占；关闭插件后此处自然消失（surfaces 为空），
+// 收件箱/任务卡等原有内容不受影响（禁用回退完整性）。点击标题去文件预览全屏。
+function WorkspaceSurfaces() {
+  const surfaces = useStore(s => s.surfaces)
+  const pin = useStore(s => s.ui.workspaceSurfacePin)
+  if (surfaces.length === 0) return null
+  const shown = pin ? surfaces.find(x => String(x.identity.surfaceId) === pin) : surfaces[surfaces.length - 1]
+  if (!shown) return null
+  return (
+    <div className="workspace-surfaces" data-workspace-surfaces>
+      <div className="ws-head">
+        <span className="ws-title">任务页面</span>
+        <span className="ws-meta">{shown.spec?.title || '（未命名）'} · 修订 {shown.revision}</span>
+        <span style={{ flex: 1 }} />
+        <button className="icon-btn" title={pin ? '取消固定（跟随最新）' : '固定此页（新页面不抢占）'}
+          onClick={() => store.setUI({ workspaceSurfacePin: pin ? null : String(shown.identity.surfaceId) })}>
+          {pin ? '📍' : '📌'}
+        </button>
+        <button className="icon-btn" title="在文件预览中打开" onClick={() => store.openSurface(String(shown.identity.surfaceId))}>
+          ↗
+        </button>
+      </div>
+      <div className="ws-body">
+        <SurfaceView snapshot={shown} />
+      </div>
+    </div>
+  )
+}

src/store.ts

@@ -27,6 +27,7 @@ import type {
   Project,
   Run,
   StreamEvent,
+  SurfaceMeta,
   SurfaceSnapshot,
   TodoList
 } from './contracts'
@@ -58,6 +59,8 @@ export interface UIState {
   rightTab: 'work' | 'files'
   /** 文件入口子视图：列表 / 预览（预览标签存在时才有意义）。 */
   filesView: 'list' | 'preview'
+  /** U6：工作区任务页固定（surfaceId；null=跟随最新；固定后新页面不抢占显示）。 */
+  workspaceSurfacePin: string | null
   /** 收件箱筛选：全部 / 待处理。铃铛打开时切到待处理。 */
   inboxFilter: 'all' | 'todo'
   theme: ThemeChoice
@@ -99,6 +102,8 @@ interface AppState {
   artifacts: Artifact[]
   /** generative-ui：会话内已保存页面（surface.updated 投影；按 surfaceId 存最新修订）。 */
   surfaces: SurfaceSnapshot[]
+  /** generative-ui U6：项目级跨会话页面聚合（打开项目时权威装载）。 */
+  projectSurfaces: SurfaceMeta[]
   cards: ActivityCard[]
   projectCards: ActivityCard[]
   inboxScope: 'conv' | 'project'
@@ -125,7 +130,7 @@ const DEFAULT_UI: UIState = {
   rightWidth: 360,
   rightCollapsed: false,
   rightTab: 'work',
-  filesView: 'list',
+filesView: 'list', workspaceSurfacePin: null,
   inboxFilter: 'all',
   activeWorkspace: null,
   theme: 'dark',
@@ -168,7 +173,7 @@ let state: AppState = {
   contextObs: {},
   projects: [], currentProjectId: null, tasks: [], me: null, currentConvId: null,
   messages: [], runs: [], activeHitl: [], lastSeq: 0, live: null,
-  plan: null, todos: null, artifacts: [], surfaces: [], cards: [], projectCards: [], inboxScope: 'conv', runtimeMock: false, profiles: [], pluginPanels: [],
+  plan: null, todos: null, artifacts: [], surfaces: [], projectSurfaces: [], cards: [], projectCards: [], inboxScope: 'conv', runtimeMock: false, profiles: [], pluginPanels: [],
   serverWorkspaces: [],
   ui: loadUI(), connected: false, posting: false, error: null, toast: null,
   outbox: [], outboxDraining: false,
@@ -374,7 +379,7 @@ export const store = {
 
   async openConversation(convId: string) {
     if (sse) { sse.close(); sse = null }
-    set({ currentConvId: convId, messages: [], runs: [], activeHitl: [], lastSeq: 0, live: null, plan: null, todos: null, cards: [], surfaces: [], inboxScope: 'conv', outbox: [], outboxDraining: false, posting: false })
+    set({ currentConvId: convId, messages: [], runs: [], activeHitl: [], lastSeq: 0, live: null, plan: null, todos: null, cards: [], surfaces: [], projectSurfaces: [], inboxScope: 'conv', outbox: [], outboxDraining: false, posting: false })
     persistConvId(convId)
     // 空态时打开的预览标签（'_' 键）随会话进入一起迁移，不留在不可见的孤儿键下。
     if ((state.previewTabs['_'] ?? []).length > 0) {
@@ -385,6 +390,7 @@ export const store = {
       })
     }
     // U4/R5：已保存页面从权威快照重载（刷新/断线恢复；事件流只做增量投影）。
+    api.projectSurfaces(state.currentProjectId ?? '').then(list => { if (state.currentConvId === convId) set({ projectSurfaces: list ?? [] }) }).catch(() => {})
     api.surfaceList(convId).then(list => {
       if (state.currentConvId !== convId) return
       set({ surfaces: list ?? [] })

src/surface.test.ts

@@ -57,3 +57,21 @@ describe('surface.updated 可见性联动', () => {
     expect(store.getState().surfaces.some(x => String(x.identity.surfaceId) === 'sv2')).toBe(true)
   })
 })
+
+describe('U6 工作区任务页', () => {
+  it('pin 固定后新页面事件不改变固定对象；取消后跟随最新', () => {
+    store.setUI({ workspaceSurfacePin: null })
+    store.applyEvent(surfEvent(201, 'w1', 1, '第一页'))
+    const first = store.getState().ui.workspaceSurfacePin
+    expect(first).toBeNull() // 默认跟随（不自动 pin）
+    // 用户固定 w1
+    store.setUI({ workspaceSurfacePin: 'w1' })
+    store.applyEvent(surfEvent(202, 'w2', 1, '第二页'))
+    // pin 不变，且 surfaces 数组两页并存（禁用回退时容器随空数组自然消失）
+    expect(store.getState().ui.workspaceSurfacePin).toBe('w1')
+    const w2 = store.getState().surfaces.find(x => String(x.identity.surfaceId) === 'w2')
+    expect(w2?.spec.title).toBe('第二页')
+    store.setUI({ workspaceSurfacePin: null })
+    expect(store.getState().ui.workspaceSurfacePin).toBeNull()
+  })
+})