chore: add "engines" field

Author: gameroman

packages/next-auth/package.json

@@ -112,5 +112,8 @@
     "next": "15.3.1",
     "nodemailer": "^7.0.7",
     "react": "^18.2.0"
+  },
+  "engines": {
+    "node": ">=18"
   }
 }