- Fix assign_tag sending Content-Type header with no body
- Mark collectives_update_collective as idempotent (no ETag involved)
- Raise OCSError when 'data' key missing instead of silent fallback
- Tighten color validator to 3 or 6 hex chars only
- Add comment explaining null emoji semantics in set_page_emoji
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>