Fix session cookie configuration and add debugging for authentication issues

backend/src/index.js

@@ -18,7 +18,10 @@ app.use(helmet({
 }));
 app.use(cors({
   origin: process.env.FRONTEND_URL || true,
-  credentials: true
+  credentials: true,
+  methods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS'],
+  allowedHeaders: ['Content-Type', 'Authorization', 'Cookie'],
+  exposedHeaders: ['Set-Cookie']
 }));
 app.use(express.json());