fix(design): separate progress from chat replies

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

@@ -93,6 +93,39 @@ describe('youth AI Design Canvas page', () => {
     expect(screen.queryByText(/规格版本|编译器|生成策略|字段决策/)).not.toBeInTheDocument();
   });
 
+  it('presents unfinished AI output as progress instead of a chat reply', () => {
+    prepareWorkspace();
+    const unfinishedDraft = '收到，我们要收到，我们要制作一张社团活动海报。';
+    useImageWorkspaceStore.setState({
+      assistantStreams: { 'operation-chat-1': unfinishedDraft },
+      pendingOperations: {
+        'operation-chat-1': {
+          id: 'operation-chat-1',
+          label: '发送创作想法',
+          command: {
+            kind: 'apply_input',
+            workspaceId: 'workspace-1',
+            sessionId: 'session-1',
+            expectedDirectionRevision: 4,
+            clientOperationId: 'operation-chat-1',
+            input: { kind: 'chat', message: '做一张社团活动海报' },
+          },
+          status: 'submitting',
+          error: null,
+          clearDraftPaths: [],
+          clearChatDraft: true,
+        },
+      },
+    });
+
+    render(<ImageCanvas />);
+
+    const conversation = screen.getByTestId('image-workspace-conversation');
+    expect(within(conversation).getByRole('status')).toHaveTextContent('AI 正在整理你的想法');
+    expect(within(conversation).getByText('我已经整理了用途、受众和初步概念，请确认右侧建议。')).toBeInTheDocument();
+    expect(within(conversation).queryByText(unfinishedDraft)).not.toBeInTheDocument();
+  });
+
   it('invites a free description and does not turn a legacy decision prompt into a form', () => {
     const workspace = designWorkspaceFixture({
       form: designFormFixture({

tests/unit/image-workspace-store.test.ts

@@ -74,6 +74,14 @@ class FakeEventSource {
   }
 }
 
+function deferred<T>() {
+  let resolve!: (value: T) => void;
+  const promise = new Promise<T>((resolvePromise) => {
+    resolve = resolvePromise;
+  });
+  return { promise, resolve };
+}
+
 async function loadedStore(eventSource = new FakeEventSource()) {
   openEventsMock.mockResolvedValue(eventSource as unknown as EventSource);
   await useImageWorkspaceStore.getState().load();
@@ -110,6 +118,87 @@ describe('V2 Living Form store', () => {
     expect(openEventsMock).toHaveBeenCalledWith('workspace-1', 'session-1', undefined);
   });
 
+  it('closes an obsolete event source when a replacement connection wins the race', async () => {
+    const workspace = designWorkspaceFixture();
+    useImageWorkspaceStore.setState({
+      status: 'ready',
+      activeWorkspaceId: workspace.workspace.workspaceId,
+      workspace,
+    });
+    const firstOpen = deferred<EventSource>();
+    const secondOpen = deferred<EventSource>();
+    const firstSource = new FakeEventSource();
+    const secondSource = new FakeEventSource();
+    openEventsMock
+      .mockReturnValueOnce(firstOpen.promise)
+      .mockReturnValueOnce(secondOpen.promise);
+
+    useImageWorkspaceStore.getState().connectEvents();
+    useImageWorkspaceStore.getState().disconnectEvents();
+    useImageWorkspaceStore.getState().connectEvents();
+
+    firstOpen.resolve(firstSource as unknown as EventSource);
+    await Promise.resolve();
+    secondOpen.resolve(secondSource as unknown as EventSource);
+    await vi.waitFor(() => expect(openEventsMock).toHaveBeenCalledTimes(2));
+
+    expect(firstSource.close).toHaveBeenCalledOnce();
+    expect(secondSource.close).not.toHaveBeenCalled();
+  });
+
+  it('allows a new event connection after opening the previous one failed', async () => {
+    const workspace = designWorkspaceFixture();
+    const recoveredSource = new FakeEventSource();
+    useImageWorkspaceStore.setState({
+      status: 'ready',
+      activeWorkspaceId: workspace.workspace.workspaceId,
+      workspace,
+    });
+    openEventsMock
+      .mockRejectedValueOnce(new Error('temporary event connection failure'))
+      .mockResolvedValueOnce(recoveredSource as unknown as EventSource);
+
+    useImageWorkspaceStore.getState().connectEvents();
+    await vi.waitFor(() => expect(useImageWorkspaceStore.getState().eventState).toBe('degraded'));
+    useImageWorkspaceStore.getState().connectEvents();
+    await vi.waitFor(() => expect(openEventsMock).toHaveBeenCalledTimes(2));
+
+    expect(recoveredSource.close).not.toHaveBeenCalled();
+  });
+
+  it('uses assistant chunk indexes to ignore replayed deltas', async () => {
+    const source = await loadedStore();
+    const baseEvent = {
+      type: 'design.assistant.delta',
+      workspaceId: 'workspace-1',
+      directionId: 'direction-1',
+      clientOperationId: 'operation-chat-1',
+      directionRevision: 4,
+    } as const;
+    source.emit('design.assistant.delta', {
+      ...baseEvent,
+      id: 'session-1:7',
+      chunkIndex: 0,
+      delta: '收到',
+    });
+    source.emit('design.assistant.delta', {
+      ...baseEvent,
+      id: 'session-1:7-replayed',
+      chunkIndex: 0,
+      delta: '收到',
+    });
+    source.emit('design.assistant.delta', {
+      ...baseEvent,
+      id: 'session-1:8',
+      chunkIndex: 1,
+      delta: '，正在整理',
+    });
+
+    expect(useImageWorkspaceStore.getState().assistantStreams).toEqual({
+      'operation-chat-1': '收到，正在整理',
+    });
+  });
+
   it('keeps a field draft separate until the direct edit succeeds', async () => {
     await loadedStore();
     useImageWorkspaceStore.getState().setFieldDraft('output.aspect_ratio', '16:9');