chore(deps): update dependency nuxt to v3.21.0 (#2474)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

packages/docs/package.json

@@ -20,7 +20,7 @@
     "@nuxtjs/mdc": "0.20.0",
     "@unocss/nuxt": "66.6.0",
     "gh-pages": "6.3.0",
-    "nuxt": "3.20.2",
+    "nuxt": "3.21.0",
     "vitest": "3.2.4",
     "zx": "8.8.5"
   }

packages/playground-nuxt/package.json

@@ -13,7 +13,7 @@
     "vue-recaptcha": "workspace:^"
   },
   "devDependencies": {
-    "nuxt": "3.20.2",
+    "nuxt": "3.21.0",
     "vue": "3.5.27",
     "vue-router": "4.6.4"
   }