* fix(scss): remove top-level parent selector for Dart Sass compatibility
Dart Sass strictly disallows top-level parent selectors (`&`), which causes build failures on newer Hugo versions (e.g. 0.158.0+).
* feat(styles): refactor special styles for friends and search layouts
* fix(seo): restructure head partial, fix Twitter social and SEO improvements
- Split head template into dedicated partial hierarchy for better maintainability
- Add full Twitter Cards support with dynamic site and creator metadata
- Update social media link prefix from twitter.com to x.com and rename label to X
- Fix Twitter/X share button and Buffer via parameter handling
- Add Mastodon verification meta tags and rel="me" links
- Improve SEO structured data for both homepage and blog posts
- Add test site configuration and test avatar asset
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Co-authored-by: Cell <1024@lruihao.cn>
Samir Paul