fix: change Next.js rewrites to redirects for short links to prevent proxy 500 error

client/next.config.ts

@@ -2,11 +2,12 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   output: 'standalone',
-  async rewrites() {
+  async redirects() {
     return [
       {
         source: '/l/:slug',
-        destination: `${process.env.INTERNAL_BACKEND_URL || 'http://localhost:4001'}/l/:slug`
+        destination: '/api/l/:slug',
+        permanent: false
       }
     ];
   }