Two ZFC fixes:
1. Boot marker file (hq-zee5n): Changed IsRunning() to query
tmux.HasSession() directly instead of checking marker file
freshness with TTL. Removed stale marker check from doctor.
2. Branch pattern matching (hq-zwuh6): Replaced hardcoded "polecat/"
strings with constants.BranchPolecatPrefix for consistency.
Also removed 60-second WaitForCommand blocking from crew Start()
which was causing gt crew start to hang.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>