feat: set up authentication infrastructure with NextAuth.js v5

- Install next-auth@beta, bcryptjs, zod, and @auth/prisma-adapter
- Create auth.ts with credentials provider and JWT session strategy
- Create auth.config.ts for edge-compatible middleware configuration
- Add NextAuth type extensions for session and JWT
- Create API route handler for authentication
- Configure environment variables for NextAuth
- Add AUTH_SETUP.md documentation

Task: 1. Set up authentication infrastructure
Requirements: 1.1, 2.1

package.json

@@ -13,14 +13,19 @@
     "icons:info": "node scripts/svg-to-png.js"
   },
   "dependencies": {
+    "@auth/prisma-adapter": "^2.11.1",
     "@prisma/client": "^5.7.1",
+    "bcryptjs": "^3.0.3",
     "lucide-react": "^0.294.0",
     "mysql2": "^3.15.3",
     "next": "14.0.4",
+    "next-auth": "^5.0.0-beta.30",
     "react": "^18",
-    "react-dom": "^18"
+    "react-dom": "^18",
+    "zod": "^4.1.13"
   },
   "devDependencies": {
+    "@types/bcryptjs": "^2.4.6",
     "@types/node": "^20",
     "@types/react": "^18",
     "@types/react-dom": "^18",