chore: switch from standalone to normal next start

- Remove output:standalone from next.config.ts
- Remove postbuild standalone copy script
- Change start script from standalone/server.js to next start
- Update PM2 to run pnpm start

next.config.ts

@@ -39,7 +39,6 @@ const nextConfig: NextConfig = {
 
 	// Disable Next.js telemetry
 	productionBrowserSourceMaps: false,
-	output: "standalone",
 
 	// Add caching headers for static assets
 	async headers() {