Add production Docker setup

- Dockerfile: multi-stage build (deps → builder → standalone runner)
- docker-compose.prod.yml: app on port 3010 + PostgreSQL 16
- entrypoint.sh: runs prisma migrate deploy then starts node server
- next.config.ts: standalone output for minimal Docker image
- .dockerignore: exclude dev files from build context

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

next.config.ts

@@ -1,7 +1,7 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  /* config options here */
+  output: "standalone",
 };
 
 export default nextConfig;