Rebased and enhanced version of PR #287 by @ccqqlo:
- _run_git() now returns stderr on failure instead of empty string,
so the UI can surface actionable git error messages
- Added _split_remote_ref() to split tracking refs like origin/master
into separate remote + branch args for git pull
- Ignore untracked files in stash decision (--untracked-files=no) to
prevent misleading stash-pop failures
- Fail early with clear message on unresolved merge conflicts
- 4 unit tests covering stderr, stdout fallback, exit code, and ref splitting
Based on work by @ccqqlo in PR #287.
Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
