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/pages/SettingsPage.tsx

@@ -34,6 +34,7 @@ import { useConfigStore, selectCliTools, selectDefaultCliTool, selectUserPrefere
 import type { CliToolConfig, UserPreferences } from '@/types/store';
 import { cn } from '@/lib/utils';
 import { LanguageSwitcher } from '@/components/layout/LanguageSwitcher';
+import { IndexManager } from '@/components/shared/IndexManager';
 
 // ========== CLI Tool Card Component ==========
 
@@ -626,6 +627,9 @@ export function SettingsPage() {
       {/* Rules */}
       <RulesSection />
 
+      {/* Index Manager */}
+      <IndexManager />
+
       {/* Reset Settings */}
       <Card className="p-6 border-destructive/50">
         <h2 className="text-lg font-semibold text-foreground flex items-center gap-2 mb-4">