fix: update Prisma client configuration and test files for Prisma 7.x compatibility

src/lib/prisma.ts

@@ -1,6 +1,10 @@
 import { PrismaClient } from '@prisma/client'
 import { PrismaPg } from '@prisma/adapter-pg'
 import pg from 'pg'
+import dotenv from 'dotenv'
+
+// Load .env file if it exists
+dotenv.config()
 
 const globalForPrisma = globalThis as unknown as {
   prisma: PrismaClient | undefined