v0.6.0

• Changed: sync SKILL/ARCHITECTURE/README with the API migration + new artifacts
• Changed: remove dead code and stale comments after the API migration
• Added: gather WG status, area, and Additional Resources into group.md
• Added: fall back to the IETF mirror archive for off-IETF mailing lists
• Changed: fetch charter from published text artifact, not HTML scraping
• Changed: send a consistent, versioned User-Agent on every fetch
• Fixed: request markdown for minutes/agenda; clean HTML-authored ones
• Changed: document API-mandatory policy in ARCHITECTURE
• Changed: gather meetings, materials, and polls via Datatracker API
• Changed: list WG documents via Datatracker API, not documents-page scraping
• Changed: resolve group metadata via Datatracker API, not About-page scraping