chore: configure next.config for Elysia server compatibility

next.config.ts

@@ -1,7 +1,8 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  /* config options here */
+  // Elysia is Bun-native and must not be bundled by Next.js
+  serverExternalPackages: ["elysia", "@elysiajs/eden"],
 };
 
 export default nextConfig;