fix(api): security hardening — helmet + auth rate limiting (#641)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

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({