fix: backend port 3001 -> 3002 to match Caddy upstream config

Caddy routes /api/* and /webhooks/* to 172.20.1.238:3002 but the
docker-compose had PORT=3001 and bound port 3001. Changed:
- PORT env var: 3001 -> 3002
- Port binding: 0.0.0.0:3002:3002
- Health check: localhost:3002/health
- Next.js rewrites: localhost:3001 -> localhost:3002
- Frontend port: 127.0.0.1 -> 0.0.0.0 (Caddy remote access)

frontend/next-env.d.ts

@@ -1,6 +1,6 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/dev/types/routes.d.ts";
+import "./.next/types/routes.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

frontend/next.config.js

@@ -6,11 +6,11 @@ const nextConfig = {
     return [
       {
         source: '/api/:path*',
-        destination: 'http://localhost:3001/api/:path*',
+        destination: 'http://localhost:3002/api/:path*',
       },
       {
         source: '/webhooks/:path*',
-        destination: 'http://localhost:3001/webhooks/:path*',
+        destination: 'http://localhost:3002/webhooks/:path*',
       },
     ];
   },