git_ui: Prepare review action with owned base ref directly (#58156)

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A
0d31b26050Xiaobo Liu committed on 6/2/2026, 9:34:27 AM· committed by GitHubparent4ef7e16
1 file changedLine totals unavailable