fix(desktop): add tauri-plugin-mcp setupPluginListeners() for dev debugging

The tauri-plugin-mcp was registered in Rust but the frontend never called
setupPluginListeners(), causing all DOM-related MCP operations (execute_js,
query_page, type_text) to timeout. This fix enables proper dev debugging
via tauri-mcp tools.

desktop/src/main.tsx

@@ -5,6 +5,7 @@ import './index.css';
 import { ToastProvider } from './components/ui/Toast';
 import { GlobalErrorBoundary } from './components/ui/ErrorBoundary';
 import { initWebMCPTools } from './lib/webmcp-tools';
+import { setupPluginListeners } from 'tauri-plugin-mcp';
 
 // Global error handler for uncaught errors
 const handleGlobalError = (error: Error, errorInfo: React.ErrorInfo) => {
@@ -29,6 +30,13 @@ const handleGlobalReset = () => {
 // Initialize WebMCP debugging tools (dev mode only, Chrome 146+)
 initWebMCPTools();
 
+// Initialize tauri-plugin-mcp event listeners (dev mode only)
+if (import.meta.env.DEV) {
+  setupPluginListeners().catch((err) => {
+    console.warn('[MCP] Failed to setup plugin listeners:', err);
+  });
+}
+
 ReactDOM.createRoot(document.getElementById('root')!).render(
   <React.StrictMode>
     <GlobalErrorBoundary