feat: add server-side version update check

Logs current version on startup and checks GitHub for newer releases.
Only runs in production, output stays in server logs (no client exposure).

next.config.ts

@@ -3,6 +3,9 @@ import createNextIntlPlugin from "next-intl/plugin";
 
 const nextConfig: NextConfig = {
   output: "standalone",
+  turbopack: {
+    root: import.meta.dirname,
+  },
 };
 
 const withNextIntl = createNextIntlPlugin();