html-authoring

**[REQUIRED]** for ALL creation, updating, or editing of .html files, regardless of complexity. Snowflake renders report HTML in a strict, sandboxed environment: no inline event handlers, no eval, no runtime network calls, no remote images or CDN scripts — only a fixed set of vendored libraries served from /libs/. Author every report to these rules so it renders correctly and is safe to share. Must use whenever generating, creating, updating, or modifying an .html file (e.g. 'update the HTML report at …').