Expand ClientApiError with structured variants for connection, server, and response errors (#56214)

Self-Review Checklist:

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

Release Notes:

- N/A
7205fb9c71Conrad Irwin committed on 5/8/2026, 8:35:29 PM· committed by GitHubparente621d0d
2 files changedLine totals unavailable