## Summary
- document that `git rev-list --left-right --count upstream/main...HEAD`
returning `0 0` means the branch cannot produce a PR
- note that agents should report the branch as pushed but PR-blocked
instead of creating an empty commit just to satisfy `gh pr create`
- update the git workflow rules with this edge case

## Test plan
- npm run fmt
- npm run lint:fix
- npm run ts
- npm test

#skip-bugbot

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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Co-authored-by: Will Chen <7344640+wwwillchen@users.noreply.github.com>