fix: 修复 AI 设计任务栏同步与独立滚动

问题：生成任务未及时出现在右侧栏，任务区与会话区还会共享外层滚动。

实现：补齐 Agent 回合与 Quote 确认后的任务同步，锁定左右滚动容器并增加桌面布局和异步任务回归测试。

src/pages/ImageCanvas/index.tsx

@@ -326,7 +326,7 @@ export function ImageCanvas() {
   }
 
   return (
-    <div data-testid="image-canvas-page" className="-m-5 flex min-h-full min-w-0 flex-col overflow-hidden bg-background text-foreground sm:-m-6">
+    <div data-testid="image-canvas-page" className="-m-5 flex h-full min-h-0 min-w-0 flex-col overflow-hidden bg-background text-foreground sm:-m-6">
       <header className="glass-surface flex shrink-0 items-center justify-between gap-3 border-b border-border/70 bg-background/80 px-4 py-3 sm:px-6">
         <div className="flex min-w-0 items-center gap-3">
           <div className="flex h-9 w-9 shrink-0 items-center justify-center rounded-xl bg-brand-soft text-brand">
@@ -361,9 +361,9 @@ export function ImageCanvas() {
         </Button>
       </header>
 
-      <div className="flex min-h-0 min-w-0 flex-1 flex-col lg:flex-row">
+      <div className="flex min-h-0 min-w-0 flex-1 flex-col overflow-hidden lg:flex-row">
-        <section className="flex min-h-0 min-w-0 flex-1 flex-col">
+        <section className="flex min-h-0 min-w-0 flex-1 flex-col overflow-hidden lg:h-full">
-          <main data-testid="image-workspace-conversation" className="min-h-0 flex-1 overflow-y-auto px-4 py-5 sm:px-6">
+          <main data-testid="image-workspace-conversation" className="min-h-0 flex-1 overflow-y-auto overscroll-contain px-4 py-5 sm:px-6">
             <div className="mx-auto flex min-h-full w-full max-w-3xl flex-col pb-4">
               {workspace.messages.length === 0 ? (
                 <div data-testid="image-workspace-empty-state" className="flex flex-1 items-center justify-center py-10 text-center">
@@ -469,7 +469,9 @@ export function ImageCanvas() {
           </form>
         </section>
 
-        <aside data-testid="design-task-list" className="min-h-0 w-full shrink-0 border-t border-border/70 bg-surface-subtle/45 lg:w-80 lg:border-l lg:border-t-0">
+        <div data-testid="design-pane-divider" aria-hidden="true" className="hidden w-px shrink-0 bg-border/70 lg:block" />
+
+        <aside data-testid="design-task-list" className="min-h-0 w-full shrink-0 overflow-hidden border-t border-border/70 bg-surface-subtle/45 lg:h-full lg:w-80 lg:border-t-0">
           <div className="flex items-center justify-between border-b border-border/70 px-4 py-3">
             <div>
               <h2 className="text-sm font-semibold">生成任务</h2>
@@ -477,7 +479,7 @@ export function ImageCanvas() {
             </div>
             {hasActiveTasks ? <Clock3 className="h-4 w-4 animate-pulse text-brand" /> : null}
           </div>
-          <div className="max-h-72 space-y-3 overflow-y-auto p-3 lg:max-h-none lg:h-[calc(100%-57px)]">
+          <div data-testid="design-task-scroll" className="h-full max-h-72 space-y-3 overflow-y-auto overscroll-contain p-3 lg:h-[calc(100%-57px)] lg:max-h-none">
             {tasks.length === 0 ? (
               <div className="rounded-2xl border border-dashed border-border/80 bg-background/70 px-4 py-7 text-center">
                 <WandSparkles className="mx-auto h-5 w-5 text-muted-foreground" />

src/stores/image-workspace.ts

@@ -45,6 +45,12 @@ type ImageWorkspaceState = {
 };
 
 let inFlightLoad: Promise<DesignWorkspaceBootstrap | null> | null = null;
+const GENERATION_TASK_SYNC_ATTEMPTS = 20;
+const GENERATION_TASK_SYNC_DELAY_MS = 500;
+
+function wait(milliseconds: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, milliseconds));
+}
 
 function unavailable(error: unknown): boolean {
   return error instanceof ImageWorkspaceApiError
@@ -107,6 +113,21 @@ export const useImageWorkspaceStore = create<ImageWorkspaceState>((set, get) =>
     return workspace;
   };
 
+  const waitForGenerationTask = async (
+    workspaceId: string,
+    quoteId: string,
+  ): Promise<DesignGenerationTask[]> => {
+    for (let attempt = 0; attempt < GENERATION_TASK_SYNC_ATTEMPTS; attempt += 1) {
+      if (get().activeWorkspaceId !== workspaceId) return [];
+      const tasks = await get().refreshTasks().catch(() => []);
+      if (tasks.some((task) => task.quoteId === quoteId)) return tasks;
+      if (attempt < GENERATION_TASK_SYNC_ATTEMPTS - 1) {
+        await wait(GENERATION_TASK_SYNC_DELAY_MS);
+      }
+    }
+    throw new Error('生成请求已确认，但任务列表尚未同步，请点击刷新重试');
+  };
+
   const loadWorkspace = async (workspaceId: string): Promise<void> => {
     const [workspace, tasks] = await Promise.all([
       fetchImageWorkspaceProject(workspaceId),
@@ -251,11 +272,13 @@ export const useImageWorkspaceStore = create<ImageWorkspaceState>((set, get) =>
       const workspace = get().workspace;
       if (!workspace) throw new Error('请先选择设计项目');
       try {
-        return applyWorkspace(await sendImageWorkspaceMessage(
+        const updated = applyWorkspace(await sendImageWorkspaceMessage(
           workspace.workspaceId,
           workspace.turnRevision,
           message,
         ));
+        await get().refreshTasks().catch(() => []);
+        return updated;
       } catch (error) {
         set({ error: handleRequestError(error) });
         return await recoverRevisionConflict(error);
@@ -271,7 +294,7 @@ export const useImageWorkspaceStore = create<ImageWorkspaceState>((set, get) =>
           workspace.turnRevision,
           quoteId,
         ));
-        await get().refreshTasks().catch(() => []);
+        await waitForGenerationTask(workspace.workspaceId, quoteId);
         return updated;
       } catch (error) {
         set({ error: handleRequestError(error) });

tests/unit/image-canvas-page.test.tsx

@@ -220,6 +220,38 @@ describe('ImageCanvas Workspace-first design experience', () => {
     expect(screen.queryByText(/当前 Agent/)).not.toBeInTheDocument();
   });
 
+  it('keeps the task list visible in a 1404px desktop workspace', async () => {
+    const previousWidth = window.innerWidth;
+    Object.defineProperty(window, 'innerWidth', { configurable: true, value: 1404 });
+
+    try {
+      render(<MemoryRouter><ImageCanvas /></MemoryRouter>);
+      await screen.findByTestId('image-workspace-conversation');
+
+      expect(screen.getByTestId('design-task-list')).toBeInTheDocument();
+      expect(screen.getByTestId('design-pane-divider')).toHaveClass('lg:block');
+    } finally {
+      Object.defineProperty(window, 'innerWidth', {
+        configurable: true,
+        value: previousWidth,
+      });
+    }
+  });
+
+  it('keeps conversation and task scrolling isolated', async () => {
+    render(<MemoryRouter><ImageCanvas /></MemoryRouter>);
+    await screen.findByTestId('image-workspace-conversation');
+
+    expect(screen.getByTestId('image-canvas-page'))
+      .toHaveClass('h-full', 'overflow-hidden');
+    expect(screen.getByTestId('image-workspace-conversation'))
+      .toHaveClass('overflow-y-auto', 'overscroll-contain');
+    expect(screen.getByTestId('design-task-list'))
+      .toHaveClass('lg:h-full', 'overflow-hidden');
+    expect(screen.getByTestId('design-task-scroll'))
+      .toHaveClass('lg:h-[calc(100%-57px)]', 'overflow-y-auto', 'overscroll-contain');
+  });
+
   it('explains the project model before the first Workspace is created', async () => {
     fetchImageWorkspaceMock.mockResolvedValueOnce({
       ...bootstrapFixture,
@@ -250,6 +282,35 @@ describe('ImageCanvas Workspace-first design experience', () => {
     expect(confirmImageWorkspaceGenerationMock).not.toHaveBeenCalled();
   });
 
+  it('refreshes tasks after an Agent turn creates a generation task', async () => {
+    const queuedTask = {
+      ...taskFixture,
+      taskId: 'task-two',
+      status: 'queued' as const,
+      resultAssets: [],
+    };
+    fetchImageWorkspaceTasksMock
+      .mockResolvedValueOnce([])
+      .mockResolvedValueOnce([queuedTask]);
+
+    render(<MemoryRouter><ImageCanvas /></MemoryRouter>);
+    await screen.findByTestId('design-quote-quote-one');
+
+    const confirmationReply = workspaceFixture().messages[1].quickReplies[0];
+    fireEvent.change(screen.getByLabelText('设计需求'), {
+      target: { value: confirmationReply },
+    });
+    fireEvent.click(screen.getByRole('button', { name: '发送给设计 Agent' }));
+
+    await waitFor(() => expect(sendImageWorkspaceMessageMock).toHaveBeenCalledWith(
+      'workspace-cloud',
+      1,
+      confirmationReply,
+    ));
+    await waitFor(() => expect(fetchImageWorkspaceTasksMock).toHaveBeenCalledTimes(2));
+    expect(await screen.findByTestId('design-task-task-two')).toBeInTheDocument();
+  });
+
   it('creates a generation task only through explicit Quote confirmation', async () => {
     fetchImageWorkspaceTasksMock
       .mockResolvedValueOnce([taskFixture])
@@ -268,4 +329,28 @@ describe('ImageCanvas Workspace-first design experience', () => {
       .toHaveBeenCalledWith('workspace-cloud', 1, 'quote-one'));
     await waitFor(() => expect(fetchImageWorkspaceTasksMock).toHaveBeenCalledTimes(2));
   });
+
+  it('keeps checking after Quote confirmation until the new task becomes visible', async () => {
+    const queuedTask = {
+      ...taskFixture,
+      taskId: 'task-delayed',
+      status: 'queued' as const,
+      resultAssets: [],
+    };
+    fetchImageWorkspaceTasksMock
+      .mockResolvedValueOnce([])
+      .mockResolvedValueOnce([])
+      .mockResolvedValueOnce([queuedTask]);
+
+    render(<MemoryRouter><ImageCanvas /></MemoryRouter>);
+    await screen.findByTestId('design-quote-quote-one');
+
+    fireEvent.click(screen.getByRole('button', { name: '确认并开始生成' }));
+
+    await waitFor(() => expect(confirmImageWorkspaceGenerationMock)
+      .toHaveBeenCalledWith('workspace-cloud', 1, 'quote-one'));
+    await waitFor(() => expect(fetchImageWorkspaceTasksMock).toHaveBeenCalledTimes(3));
+    expect(await screen.findByTestId('design-task-task-delayed'))
+      .toBeInTheDocument();
+  });
 });