Lowers eslint-config-next to v15

Author: simonbs

package.json

@@ -62,7 +62,7 @@
     "@types/react-dom": "^19.2.3",
     "@typescript-eslint/parser": "^8.31.1",
     "eslint": "^9.39.1",
-    "eslint-config-next": "^16.0.3",
+    "eslint-config-next": "^15.3.4",
     "pg": "^8.16.3",
     "postcss": "^8.5.6",
     "tailwindcss": "^4.1.4",