subagenttasks

Refactor T3 (deferred): distiller from regex to stdlib html.parser

crawlers/claude_docs/md.py distills HTML via regex; stdlib html.parser.HTMLParser would be structurally robust (nesting, attributes, malformed tags). Deferred — working code behind the CommonMark gate; a rewrite needs golden-file comparison across ~10 mirrored pages plus the cm gate. Do as its own pass.