Audit and update GitHub repository metadata and community health: description (gh repo edit), topics (PUT /repos/topics, max 20), GitHub Pages link + homepage, community-health percentage via the Community Profile API, and a 16-point check checklist. Script: validate_repo.py (gh API + filesystem, auto-detect from git remote). Triggers: 'repo description', 'repo topics', 'github topics', 'github pages', 'community health', 'repo audit', 'repo metadata', 'repo checklist', 'health percentage', 'repo about'.
