Code highlighting, richer Markdown heading and footnote rendering, and README sponsor updates.
Added
- Code blocks now use Shiki syntax highlighting. Fenced code blocks render with bundled Shiki highlighting in both the app and Quick Look, so previews show language-aware colors without needing network access.
Fixed
- Footnotes now render correctly. Markdown footnote definitions and references are collected, linked, and rendered as a proper footnotes section instead of appearing as plain paragraph content.
- Inline markup works inside headings. Emphasis, links, code spans, and other inline Markdown now render correctly inside heading text while keeping generated heading anchors stable.