feat: integrate @better-auth/infra for dashboard and sentinel monitoring

apps/frontend/src/lib/api-client.ts

@@ -1,5 +1,6 @@
 import { createAuthClient } from 'better-auth/react';
 import * as api from './api';
+import { sentinelClient } from "@better-auth/infra/client";
 
 const apiBaseUrl = api.apiBaseUrl;
 
@@ -8,6 +9,7 @@ export const authClient = createAuthClient({
   fetchOptions: {
     credentials: 'include',
   },
+  plugins: [sentinelClient()],
 });
 
 export class ApiClientError extends Error {