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({