修复: 打通设计回复流式投递与结构化确认

问题：Run 完成会抢在 SSE 流式事件之前清空 pending，导致回复整块出现；无 Quote 的确认按钮又会降级为普通聊天，因此无法创建任务。

实现：为 Main 事件队列增加有界投递屏障，严格识别生成确认短语并只调用结构化 Quote Action，接入 generation capability 提示，同时补齐竞态、误触和任务对账测试。

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

@@ -348,6 +348,14 @@ describe('ImageCanvas Workspace-first design experience', () => {
         chunkIndex: 0,
         delta: '可以先增加',
       } satisfies DesignAssistantDeltaEvent);
+    });
+
+    expect(screen.getByTestId('image-workspace-conversation'))
+      .toHaveTextContent('可以先增加');
+    expect(screen.getByTestId('image-workspace-conversation'))
+      .not.toHaveTextContent('留白和水流节奏');
+
+    act(() => {
       taskEventSource.emit('design.assistant.delta', {
         id: 'session-one:3',
         type: 'design.assistant.delta',
@@ -369,34 +377,34 @@ describe('ImageCanvas Workspace-first design experience', () => {
     await waitFor(() => expect(useImageWorkspaceStore.getState().pendingTurn).toBeNull());
   });
 
-  it('refreshes tasks after an Agent turn creates a generation task', async () => {
-    const queuedTask = {
-      ...taskFixture,
-      taskId: 'task-two',
-      status: 'queued' as const,
-      resultAssets: [],
+  it('never downgrades confirmation to normal chat when no active Quote exists', async () => {
+    const workspaceWithoutQuote = workspaceFixture();
+    workspaceWithoutQuote.messages[1] = {
+      ...workspaceWithoutQuote.messages[1],
+      generationQuote: null,
     };
-    fetchImageWorkspaceTasksMock
-      .mockResolvedValueOnce([])
-      .mockResolvedValueOnce([queuedTask]);
+    fetchImageWorkspaceMock.mockResolvedValueOnce({
+      ...bootstrapFixture,
+      capabilities: {
+        ...bootstrapFixture.capabilities,
+        generation: false,
+        image: false,
+        video: false,
+      },
+    });
+    fetchImageWorkspaceProjectMock.mockResolvedValueOnce(workspaceWithoutQuote);
 
     render(<MemoryRouter><ImageCanvas /></MemoryRouter>);
-    await screen.findByTestId('design-quote-quote-one');
+    const confirmReply = await screen.findByRole('button', { name: '确认生成' });
 
-    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' }));
+    fireEvent.click(confirmReply);
 
-    await waitFor(() => expect(sendImageWorkspaceMessageMock).toHaveBeenCalledWith(
-      'workspace-cloud',
-      1,
-      confirmationReply,
-      expect.stringMatching(/^turn-/),
-    ));
-    await waitFor(() => expect(fetchImageWorkspaceTasksMock).toHaveBeenCalledTimes(2));
-    expect(await screen.findByTestId('design-task-task-two')).toBeInTheDocument();
+    expect(screen.getByRole('alert')).toHaveTextContent('当前没有可确认的生成报价');
+    expect(screen.getByLabelText('设计需求')).toHaveValue('');
+    expect(sendImageWorkspaceMessageMock).not.toHaveBeenCalled();
+    expect(confirmImageWorkspaceGenerationMock).not.toHaveBeenCalled();
+    expect(screen.getByTestId('image-workspace-composer'))
+      .toHaveTextContent('当前环境仅支持设计沟通');
   });
 
   it('creates a generation task only through explicit Quote confirmation', async () => {
@@ -425,6 +433,55 @@ describe('ImageCanvas Workspace-first design experience', () => {
     expect(await screen.findByTestId('design-task-task-two')).toBeInTheDocument();
   });
 
+  it('converts an exact composer confirmation into the structured Quote action', async () => {
+    fetchImageWorkspaceTasksMock
+      .mockResolvedValueOnce([taskFixture])
+      .mockResolvedValueOnce([{
+        ...taskFixture,
+        taskId: 'task-confirmed-from-composer',
+        quoteId: 'quote-one',
+        status: 'queued',
+        resultAssets: [],
+      }]);
+    render(<MemoryRouter><ImageCanvas /></MemoryRouter>);
+    await screen.findByTestId('design-quote-quote-one');
+
+    fireEvent.change(screen.getByLabelText('设计需求'), {
+      target: { value: '确认生成' },
+    });
+    fireEvent.click(screen.getByRole('button', { name: '发送给设计 Agent' }));
+
+    await waitFor(() => expect(confirmImageWorkspaceGenerationMock)
+      .toHaveBeenCalledWith(
+        'workspace-cloud',
+        1,
+        'quote-one',
+        expect.stringMatching(/^turn-/),
+      ));
+    expect(sendImageWorkspaceMessageMock).not.toHaveBeenCalled();
+    expect(await screen.findByTestId('design-task-task-confirmed-from-composer'))
+      .toBeInTheDocument();
+  });
+
+  it('keeps longer design questions containing confirmation words as normal chat', async () => {
+    render(<MemoryRouter><ImageCanvas /></MemoryRouter>);
+    await screen.findByTestId('design-quote-quote-one');
+    const question = '请确认这个生成图的构图是不是还需要调整';
+
+    fireEvent.change(screen.getByLabelText('设计需求'), {
+      target: { value: question },
+    });
+    fireEvent.click(screen.getByRole('button', { name: '发送给设计 Agent' }));
+
+    await waitFor(() => expect(sendImageWorkspaceMessageMock).toHaveBeenCalledWith(
+      'workspace-cloud',
+      1,
+      question,
+      expect.stringMatching(/^turn-/),
+    ));
+    expect(confirmImageWorkspaceGenerationMock).not.toHaveBeenCalled();
+  });
+
   it('renders a new task pushed by the design event stream without repeated polling', async () => {
     const queuedTask = {
       ...taskFixture,