feat(01-02): configure NextAuth.js v4 with credentials provider and JWT

- Install next-auth@4, bcryptjs, @types/bcryptjs, @types/jest
- src/types/next-auth.d.ts: extend Session/JWT with tenantId, roles, isSuperAdmin
- src/lib/auth-options.ts: CredentialsProvider + JWT/session callbacks, 24h maxAge
- src/lib/auth.ts: getServerSession() and getCurrentUser() server helpers
- src/app/api/auth/[...nextauth]/route.ts: NextAuth GET/POST handler
- src/middleware.ts: withAuth middleware protecting all routes except /login /signup /api/auth/*

package.json

@@ -15,13 +15,17 @@
   },
   "dependencies": {
     "@prisma/client": "^6.19.2",
+    "bcryptjs": "^3.0.3",
     "next": "16.1.6",
+    "next-auth": "^4.24.13",
     "prisma": "^6.19.2",
     "react": "19.2.3",
     "react-dom": "19.2.3"
   },
   "devDependencies": {
     "@tailwindcss/postcss": "^4",
+    "@types/bcryptjs": "^2.4.6",
+    "@types/jest": "^30.0.0",
     "@types/node": "^20",
     "@types/react": "^19",
     "@types/react-dom": "^19",