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/en/workspace.json

@@ -0,0 +1,29 @@
+{
+  "selector": {
+    "noWorkspace": "No workspace selected",
+    "recentPaths": "Recent Projects",
+    "noRecentPaths": "No recent projects",
+    "current": "Current",
+    "browse": "Select Folder...",
+    "removePath": "Remove from recent",
+    "ariaLabel": "Workspace selector"
+  },
+  "dialog": {
+    "title": "Select Project Folder",
+    "placeholder": "Enter project path...",
+    "help": "The path to your project directory"
+  },
+  "actions": {
+    "switch": "Switch Workspace",
+    "switchFailed": "Failed to switch workspace",
+    "switchSuccess": "Successfully switched to {path}"
+  },
+  "validation": {
+    "pathRequired": "Project path is required",
+    "invalidPath": "Invalid project path: {path}"
+  },
+  "notifications": {
+    "switching": "Switching workspace...",
+    "refreshing": "Refreshing recent paths..."
+  }
+}