Previously hitting `Publish` in the git panel would silently fail with
no error message if the git repo was new or didn't have a remote.

Now, when hitting `Publish` or attempting to push when there is no
remote using keyboard shortcuts, or using `Push To` or force push
options, an error message will be displayed.

<img width="1135" height="522" alt="Screenshot 2026-04-22 at 10 02
26 AM"
src="https://github.com/user-attachments/assets/93c5e7ee-371e-4c2c-961b-42501cbd7119"
/>

<img width="1135" height="522" alt="Screenshot 2026-04-22 at 10 02
36 AM"
src="https://github.com/user-attachments/assets/a923e5f2-4099-45b5-8fe2-eb78f4fc9f10"
/>


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:

- Fixed handling of `git push` when there is no remote available to push
to