fix(design): separate progress from chat replies

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');