feat(vue-router): add `styles` to Vue `RouteMatchExtensions` augmentation

Summary

The RouteMatchExtensions interface in packages/vue-router/src/Matches.tsx is missing a styles field, unlike the React and Solid counterparts which include it.

This gap pre-dates PR #7311 (feat: add support for deferred head loading), which added key?: string support to the existing fields but did not introduce the missing styles entry for Vue.

Required Change

Add the following field to the RouteMatchExtensions module augmentation in packages/vue-router/src/Matches.tsx:

styles?: Array<
  (Vue.ComponentOptions['style'] & { key?: string }) | undefined
>

This should be placed alongside meta, links, scripts, and headScripts to match the React/Solid augmentations and provide full type coverage for keyed/deferred head().styles in Vue.

References

• Raised in: https://github.com/TanStack/router/pull/7311#discussion_r3176273872
• Related PR: https://github.com/TanStack/router/pull/7311

/cc @romulovalez

Open packages/vue-router/src/Matches.tsx and read the RouteMatchExtensions module augmentation, then compare its meta, links, scripts, and headScripts fields with the React and Solid counterparts. Done means the Vue augmentation includes the requested optional styles type and provides coverage for keyed or deferred head().styles.