feat(a2ui): Implement A2UI backend with question handling and WebSocket support

- Added A2UITypes for defining question structures and answers.
- Created A2UIWebSocketHandler for managing WebSocket connections and message handling.
- Developed ask-question tool for interactive user questions via A2UI.
- Introduced platformUtils for platform detection and shell command handling.
- Centralized TypeScript types in index.ts for better organization.
- Implemented compatibility checks for hook templates based on platform requirements.

ccw/frontend/src/locales/zh/lite-tasks.json

@@ -19,6 +19,8 @@
     "title": "此会话中没有任务",
     "message": "此会话尚不包含任何任务。"
   },
+  "untitled": "无标题任务",
+  "discussionTopic": "讨论主题",
   "notFound": {
     "title": "未找到轻量任务",
     "message": "无法找到请求的轻量任务会话。"