修复分离传播结果联动高亮

- 将 propagation_seed_signature 纳入传播链选择 token
- 修复合并后的分离 mask 传播到同一帧后点击一个片段另一个不联动高亮的问题
- 同步 VideoWorkspace 的传播链 token 逻辑，保持删除和清空链路一致
- 补充 CanvasArea 回归测试，覆盖同 seed signature 的分离传播片段联动选中
- 更新项目指南和设计冻结文档中的联动规则

src/components/CanvasArea.test.tsx

@@ -466,6 +466,48 @@ describe('CanvasArea', () => {
     expect(screen.getByText('当前图层: 胆囊 #21')).toBeInTheDocument();
   });
 
+  it('selects all separated propagated pieces with the same seed signature on the frame', () => {
+    useStore.setState({
+      maskPreviewOpacity: 35,
+      masks: [
+        {
+          id: 'annotation-20',
+          annotationId: '20',
+          frameId: 'frame-1',
+          pathData: 'M 10 10 L 30 10 L 30 30 Z',
+          label: 'Merged object',
+          color: '#facc15',
+          segmentation: [[10, 10, 30, 10, 30, 30]],
+          metadata: {
+            source: 'sam2.1_hiera_tiny_propagation',
+            propagated_from_frame_id: 'seed-frame',
+            propagation_seed_signature: 'merged-seed-signature',
+          },
+        },
+        {
+          id: 'annotation-21',
+          annotationId: '21',
+          frameId: 'frame-1',
+          pathData: 'M 80 80 L 100 80 L 100 100 Z',
+          label: 'Merged object',
+          color: '#facc15',
+          segmentation: [[80, 80, 100, 80, 100, 100]],
+          metadata: {
+            source: 'sam2.1_hiera_tiny_propagation',
+            propagated_from_frame_id: 'seed-frame',
+            propagation_seed_signature: 'merged-seed-signature',
+          },
+        },
+      ],
+    });
+
+    render(<CanvasArea activeTool="edit_polygon" frame={frame} />);
+    fireEvent.click(screen.getAllByTestId('konva-path')[0]);
+
+    expect(useStore.getState().selectedMaskIds).toEqual(['annotation-20', 'annotation-21']);
+    expect(screen.getAllByTestId('konva-group').map((group) => group.getAttribute('data-opacity'))).toEqual(['0.5', '0.5']);
+  });
+
   it('does not render stored GT seed points as visible editable handles', () => {
     useStore.setState({
       masks: [

src/components/CanvasArea.tsx

@@ -89,6 +89,9 @@ function propagationLineageTokens(mask: Mask): Set<string> {
   if (typeof metadata.propagation_seed_key === 'string' && metadata.propagation_seed_key.length > 0) {
     tokens.add(`seed-key:${metadata.propagation_seed_key}`);
   }
+  if (typeof metadata.propagation_seed_signature === 'string' && metadata.propagation_seed_signature.length > 0) {
+    tokens.add(`seed-signature:${metadata.propagation_seed_signature}`);
+  }
   return tokens;
 }
 

src/components/VideoWorkspace.tsx

@@ -292,6 +292,9 @@ const propagationLineageTokens = (mask: Mask): Set<string> => {
   if (typeof metadata.propagation_seed_key === 'string' && metadata.propagation_seed_key.length > 0) {
     tokens.add(`seed-key:${metadata.propagation_seed_key}`);
   }
+  if (typeof metadata.propagation_seed_signature === 'string' && metadata.propagation_seed_signature.length > 0) {
+    tokens.add(`seed-signature:${metadata.propagation_seed_signature}`);
+  }
   return tokens;
 };