build(deps-dev): bump @unocss/transformer-variant-group in /frontend

Bumps [@unocss/transformer-variant-group](https://github.com/unocss/unocss/tree/HEAD/packages-presets/transformer-variant-group) from 65.5.0 to 66.0.0.
- [Release notes](https://github.com/unocss/unocss/releases)
- [Commits](https://github.com/unocss/unocss/commits/v66.0.0/packages-presets/transformer-variant-group)

---
updated-dependencies:
- dependency-name: "@unocss/transformer-variant-group"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

frontend/package.json

@@ -33,7 +33,7 @@
     "@types/node": "^22.13.5",
     "@typescript-eslint/eslint-plugin": "^8.22.0",
     "@unocss/transformer-directives": "^65.4.3",
-    "@unocss/transformer-variant-group": "^65.5.0",
+    "@unocss/transformer-variant-group": "^66.0.0",
     "@vitejs/plugin-vue": "^5.0.3",
     "@vue/eslint-config-typescript": "^13.0.0",
     "@vue/tsconfig": "^0.7.0",