Fixes gt-v07fl: Polecat lifecycle cleanup for stale worktrees and git
tracking conflicts.
Changes:
1. Add .claude/ to .gitignore (prevents untracked file accumulation)
2. Add beads runtime state patterns to .gitignore (prevents future tracking)
3. Remove .beads/ runtime state from git tracking (mq/, issues.jsonl, etc.)
- Formulas and config remain tracked (needed for go install)
- Created follow-up gt-mpyuq for formulas refactor
4. Add DetectStalePolecats() to polecat manager for identifying cleanup candidates
5. Add CountCommitsBehind() to git package for staleness detection
6. Add `gt polecat stale <rig>` command for stale polecat detection/cleanup
- Shows polecats without active sessions
- Identifies polecats far behind main (configurable threshold)
- Optional --cleanup flag to auto-nuke stale polecats
The existing `gt polecat gc` command handles branch cleanup.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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