fix(api): helmet security headers + auth endpoint rate limiting

apps/api/src/auth/auth.controller.ts

@@ -106,7 +106,7 @@ export class AuthController {
   // @SkipCsrf avoids double-protection conflicts.
   // See: https://www.better-auth.com/docs/reference/security
   @SkipCsrf()
-  @Throttle({ strict: { limit: 10, ttl: 60000 } })
+  @Throttle({ default: { ttl: 60_000, limit: 5 } })
   async handleAuth(@Req() req: ExpressRequest, @Res() res: ExpressResponse): Promise<void> {
     // Extract client IP for logging
     const clientIp = this.getClientIp(req);

apps/api/src/main.ts

@@ -1,6 +1,7 @@
 import { NestFactory } from "@nestjs/core";
 import { RequestMethod, ValidationPipe } from "@nestjs/common";
 import cookieParser from "cookie-parser";
+import helmet from "helmet";
 import { AppModule } from "./app.module";
 import { getTrustedOrigins } from "./auth/auth.config";
 import { GlobalExceptionFilter } from "./filters/global-exception.filter";
@@ -33,6 +34,14 @@ async function bootstrap() {
   // Enable cookie parser for session handling
   app.use(cookieParser());
 
+  // Enable helmet security headers
+  app.use(
+    helmet({
+      contentSecurityPolicy: false, // Let Next.js handle CSP
+      crossOriginEmbedderPolicy: false,
+    })
+  );
+
   // Enable global validation pipe with transformation
   app.useGlobalPipes(
     new ValidationPipe({