feat(design): integrate agent activity timeline

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

@@ -1206,6 +1206,64 @@ describe('V2 Living Form store', () => {
       .toMatchObject({ status: 'unknown', steps: [{ stage: 'reviewing_context' }] });
   });
 
+  it('preserves an earlier unknown activity when another chat starts', async () => {
+    await loadedStore();
+    const submission = deferred<Awaited<ReturnType<typeof submitImageWorkspaceCommand>>>();
+    operationIdMock.mockReturnValueOnce('operation-chat-2');
+    submitCommandMock.mockReturnValueOnce(submission.promise);
+    useImageWorkspaceStore.setState({
+      chatDraft: '再补充一只小兔子',
+      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: '先画一只小熊' },
+          },
+          status: 'unknown',
+          error: '结果尚未确认',
+          clearDraftPaths: [],
+          clearChatDraft: true,
+          baseRawTurnSequence: 1,
+        },
+      },
+      assistantActivities: {
+        'operation-chat-1': {
+          workspaceId: 'workspace-1',
+          directionId: 'direction-1',
+          status: 'unknown',
+          turnId: null,
+          steps: [{ stage: 'reviewing_context', message: '正在整理上下文' }],
+        },
+      },
+    });
+
+    const sendPromise = useImageWorkspaceStore.getState().sendChat();
+
+    expect(useImageWorkspaceStore.getState().assistantActivities).toMatchObject({
+      'operation-chat-1': {
+        status: 'unknown',
+        steps: [{ stage: 'reviewing_context' }],
+      },
+    });
+    expect(useImageWorkspaceStore.getState().pendingOperations).toMatchObject({
+      'operation-chat-1': { status: 'unknown' },
+      'operation-chat-2': { status: 'submitting' },
+    });
+
+    submission.resolve({
+      clientOperationId: 'operation-chat-2',
+      runId: 'run-2',
+      workspace: designWorkspaceFixture(),
+    });
+    await sendPromise;
+  });
+
   it('expires quote blockers only after the canonical Specification changes', async () => {
     await loadedStore();
     const blocker = {