git: Only save dirty files during staging (#41047)

Closes #40581

Release Notes:

- git: No longer save clean files when staging (to avoid triggering
unnecessary rebuilds in external file watchers like vite)
1ce9a85a1aConrad Irwin committed on 10/23/2025, 8:53:19 PM· committed by GitHubparent1966d4c
2 files changedLine totals unavailable