fix: simplify prisma.config.ts and exclude it from Next.js tsconfig

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tsconfig.json

@@ -22,5 +22,5 @@
     }
   },
   "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
-  "exclude": ["node_modules"]
+  "exclude": ["node_modules", "prisma.config.ts", "prisma/seed.ts"]
 }