fix: update Prisma client configuration and cleanup script

src/lib/prisma.ts

@@ -1,13 +1,11 @@
 import { PrismaClient } from '@prisma/client'
 
-// Load .env file if it exists
-require('dotenv').config()
-
 const globalForPrisma = globalThis as unknown as {
   prisma: PrismaClient | undefined
 }
 
 // Detect database provider from environment (default to sqlite for local development)
+// Next.js automatically loads environment variables from .env, .env.development, .env.production
 const databaseProvider = process.env.DATABASE_PROVIDER || 'sqlite'
 const databaseUrl = process.env.DATABASE_URL