🐛 fix(ai-panel): 隔离面板与消息级渲染异常避免整块白屏

- 为 AI 面板保留本地错误边界与重新加载兜底
- 为单条消息增加渲染隔离，异常消息不再拖垮整段对话
- 补充面板与消息渲染错误上下文，便于后续定位

frontend/src/App.ai-panel-error-boundary.test.ts

@@ -9,12 +9,14 @@ const appSource = readFileSync(
 
 describe('AI panel lazy-load guard', () => {
   it('keeps AI panel failures scoped to the panel area with retry support', () => {
-    expect(appSource).toContain('const createLazyAIChatPanel = () => React.lazy(() => import(\'./components/AIChatPanel\'));');
+    expect(appSource).toContain("import AIChatPanel from './components/AIChatPanel';");
     expect(appSource).toContain('class AIPanelErrorBoundary extends React.Component');
     expect(appSource).toContain('<AIPanelErrorBoundary');
+    expect(appSource).toContain('key={aiPanelRenderNonce}');
     expect(appSource).toContain('AI 面板加载失败');
     expect(appSource).toContain('重新加载');
     expect(appSource).toContain('setAiPanelRenderNonce((current) => current + 1)');
-    expect(appSource).toContain('<LazyAIChatPanel width={aiPanelRenderWidth}');
+    expect(appSource).toContain('<AIChatPanel width={aiPanelRenderWidth}');
+    expect(appSource).not.toContain('const loadAIChatPanelModule = async (retryNonce: number) => {');
   });
 });