add login validation

src/main.ts

@@ -0,0 +1,14 @@
+import { NestFactory } from '@nestjs/core';
+import { AppModule } from './app.module';
+
+async function bootstrap() {
+  const app = await NestFactory.create(AppModule);
+  app.enableCors({
+    origin: ["http://localhost:3000"], // 👈 array is safer
+    methods: ["GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"],
+    allowedHeaders: ["Content-Type", "Authorization"],
+    credentials: true,
+  });
+  await app.listen(process.env.PORT ?? 3001);
+}
+bootstrap();