chore(deps): update dependency nuxt to v4

Author: renovate[bot]

package.json

@@ -18,7 +18,7 @@
     "@nuxthub/core": "^0.9.0",
     "@octokit/graphql": "^9.0.2",
     "@octokit/rest": "^22.0.0",
-    "nuxt": "^3.19.2",
+    "nuxt": "^4.1.3",
     "nuxt-webhook-validators": "^0.2.5",
     "zod": "^4.1.11"
   },