A claimed run only joined the leased set once its pipeline was built, so a
build waiting for a busy worker pool got the run swept as abandoned. Cancel
now also stops such a run, and a terminal status being overwritten is logged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013GAeg4Jo6xjZzjwy9QDWMQ