Bug 1: 2>/dev/null on critical git commands swallowed checkout failures.
Branches created from stale base (670 commits behind), carrying 56+
noise files. Fix: log all git output, fail hard on errors, add SHA
canary to verify worktree matches origin/main.
Bug 2: Gate 2 had no staleness check. Stale conflict branches blocked
re-extraction forever (0 extractions for 5 days). Fix: 2-hour threshold.
If branch >2h old and PR unmergeable, auto-close PR with audit comment,
delete branch, and re-extract. Also handles orphan branches (no PR).
Pentagon-Agent: Epimetheus <3D35839A-7722-4740-B93D-51157F7D5E70>
Pre-extraction step: find queue files already in archive, delete them,
commit + push. Runs on main worktree before extraction starts on extract
worktree. Prevents "queue duplicate reappears after reset --hard" problem
that produced 16 stale entries overnight.
Pentagon-Agent: Epimetheus <3D35839A-7722-4740-B93D-51157F7D5E70>