- Replace the fork-era Markdown integration with Comark and an explicit Shiki extension\n- Centralize OpenPencil theming, parser lifecycle, controls, and URL hardening\n- Remove Mermaid stubs and bundled math or diagram dependencies\n- Address contextual composer review findings and extend browser coverage\n\nCo-authored-by: Jason Kneen <jason.kneen@bouncingfish.com>