chore(deps): update nextjs monorepo to v15

Author: renovate[bot]

package.json

@@ -25,9 +25,9 @@
     "@types/react": "^18.3.18",
     "@types/react-dom": "^18.3.5",
     "eslint": "^8.57.1",
-    "eslint-config-next": "14.2.29",
+    "eslint-config-next": "15.3.2",
     "eslint-config-prettier": "9.1.0",
-    "next": "14",
+    "next": "15",
     "postcss": "^8.5.1",
     "prettier": "^3.4.2",
     "tailwindcss": "^3.4.17",