fix: lazy-load Prisma client to fix build-time URL parsing

- Make Prisma client initialization lazy via Proxy
- Defer database-pool import until runtime
- Add guard for empty DATABASE_URL
- Build now succeeds with Next.js 16.1.4

lib/database-pool.ts

@@ -8,6 +8,9 @@ import { env } from "./env";
 // Enhanced connection pool configuration
 const createConnectionPool = () => {
   // Parse DATABASE_URL to get connection parameters
+  if (!env.DATABASE_URL) {
+    throw new Error("DATABASE_URL environment variable is required");
+  }
   const databaseUrl = new URL(env.DATABASE_URL);
 
   const pool = new Pool({