Update nextjs monorepo to v16

Author: renovate[bot]

apps/demo/package.json

@@ -11,7 +11,7 @@
   },
   "dependencies": {
     "@davidevmod/focus-trap": "workspace:^",
-    "next": "13.4.8",
+    "next": "16.0.3",
     "react": "18.2.0",
     "react-dom": "18.2.0"
   },
@@ -24,7 +24,7 @@
     "@types/react-dom": "18.2.14",
     "autoprefixer": "10.4.22",
     "eslint": "9.39.1",
-    "eslint-config-next": "13.4.8",
+    "eslint-config-next": "16.0.3",
     "postcss": "8.5.6",
     "prettier": "3.6.2",
     "prettier-plugin-tailwindcss": "0.7.1",