v0.23.3: Merge pull request #31 from oxygenframe/release-0.23.3

Added

• Six more blocks for oxframe add (oxframe-cli): feature-grid,
  checklist, comparison, chat-messages, pull-request and
  countdown, eighteen in all, every one passing oxframe check.
• The agent skill: a request to explain or show something means a scene,
  not an answer in chat; hints for the compile errors seen most in the
  0.23.2 agent eval. No SDK code changed.