Html2Mdx

HTML -> MDX converter: the Starlight-side counterpart to Html2Typst. Same DOM-walk shape (see that file's KDoc for the upstream html2typst lineage and the deviations already made there — unrecognized tags fall back instead of crashing, inter-element whitespace is preserved), but this one was written fresh against MDX/GFM syntax rather than ported from Rust, and reuses this project's own MdxEscaper (prose + fence channels) so Dokka-derived content escapes exactly the same way myst2mdx's own MyST->MDX output does — one escaping policy, not two.

Output is body content only, meant for files under site/src/content/docs/api/ with Starlight frontmatter (at minimum title) prepended separately — this doesn't go through mystmd/myst2mdx at all, since Dokka's HTML has no MyST constructs for that pipeline to resolve.

See Html2Typst's KDoc for the anchor-wrapper/"Link copied to clipboard" finding — same fix applies here, same reason (only found via real dokkaGenerate output, see RealDokkaFixtureTest).