After squash merge, polecat branches have different commit SHAs than main
even though the content is identical. This was causing false "unpushed
commits" warnings during nuke safety checks.
Now uses `git diff` to verify if content differs from main, rather than
just counting commits ahead. If diff is empty, content is on main
(via squash merge) and nuke is safe. (gt-fo9iz)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>