chore(deps): update test packages to v4

Author: renovate[bot]

package.json

@@ -79,7 +79,7 @@
     "@nuxt/schema": "4.2.2",
     "@nuxt/test-utils": "3.21.0",
     "@types/node": "24.10.4",
-    "@vitest/coverage-v8": "3.2.4",
+    "@vitest/coverage-v8": "4.0.16",
     "@vue/test-utils": "2.4.6",
     "bumpp": "10.3.2",
     "eslint": "9.39.2",
@@ -93,7 +93,7 @@
     "typescript": "5.9.3",
     "unbuild": "3.6.1",
     "unhead": "2.0.19",
-    "vitest": "3.2.4",
+    "vitest": "4.0.16",
     "vue": "3.5.25",
     "vue-tsc": "3.1.8"
   },