@pm proposes a milestone + sub-tasks and asks for approval; on 'yes' it emits a BEGIN_SUBTASKS block, and the workflow creates the milestone + one sub-issue per line (each 'Part of #<feature>'). Sub-issues are not auto-started — maintainer @mentions an agent on each when ready. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>