Plain-JS Next config so the image boots without devDependencies

next start stops to install TypeScript when the config is a .ts file, which in
the container meant a yarn install into node_modules on every boot — slow
enough that the health check failed before the server answered.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

next.config.ts

@@ -1,7 +0,0 @@
-import type { NextConfig } from "next";
-
-const nextConfig: NextConfig = {
-  serverExternalPackages: ['better-sqlite3'],
-};
-
-export default nextConfig;