workspace: Fix captured focus when opening modals (#63512)

# Objective

- This PR fixes the captured focus in modals. 
- Fixes #63480 (and actually this was not specific to the task modal. it
was generic and applied to all modals)

## Solution

- Previously when a modal was opened the `previous_focus_handle` was
stealing the focus because it was captured in `show_modal`. The fix was
to capture it before calling `show_modal` or `reveal_stashed_modal` and
pass it to `show_modal`. That fixes the bug :) (yuhuu).

## Testing

- Tested by running the build and trying to reproduce the bug. I
couldn't reproduce it anymore.
- For testing, a reviewer also needs to test the revelal stashed modal
functionality. I did it with the file finder.

## 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 adheres to Zed's UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

---

Release Notes:

- Fixed previous window focus handle not being captured correctly when
opening modals
837264129fMatei Oprea committed on 9/2/2026, 11:59:16 AM· committed by GitHubparentd56dca8
1 file changedLine totals unavailable