Add frontend service to Docker setup and configure networking

Introduced a new `frontend` service in `docker-compose.yml`, complete with build, healthchecks, and networking. Added a multi-stage Dockerfile for the frontend, a `.dockerignore` file, and a startup script to wait for the backend. Updated Next.js configuration for Docker compatibility and added API type definitions.

frontend/next.config.ts

@@ -1,7 +1,16 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  /* config options here */
+    output: 'standalone',
+    // Ensure we can connect to the backend in Docker
+    async rewrites() {
+        return [
+            {
+                source: '/api/:path*',
+                destination: 'http://backend:8000/:path*',
+            },
+        ];
+    },
 };
 
-export default nextConfig;
+export default nextConfig;