Remove experimental Next.js config options

staleTimes, optimizePackageImports, and staticGenerationMaxConcurrency
were all experimental-only in Next.js 16. Removed them:

- staleTimes: router cache defaults are sufficient
- optimizePackageImports: Turbopack already tree-shakes lucide-react
- staticGenerationMaxConcurrency: mitigated by DATABASE_POOL_SIZE=5

Eliminates the 'Experiments (use with caution)' warning for our custom
options. Only clientTraceMetadata remains (Next.js framework default).

next.config.ts

@@ -41,17 +41,6 @@ const nextConfig: NextConfig = {
 	productionBrowserSourceMaps: false,
 	output: "standalone",
 
-	// Cache pages longer in the router cache for faster back/forward navigation
-	experimental: {
-		staleTimes: {
-			dynamic: 30,
-			static: 180,
-		},
-		optimizePackageImports: ["lucide-react"],
-		// Keep build-time DB fan-out low (shared MySQL with emulator).
-		staticGenerationMaxConcurrency: 3,
-	},
-
 	// Add caching headers for static assets
 	async headers() {
 		return [