edit_prediction: Remove diagnostic-triggered jumps (#59724)

# Objective

- Simplify edit prediction jumps enough to re-enable the staff flag.
- Defer diagnostic-triggered jump refreshes until we know we need them.

## Solution

- Remove the diagnostic refresh trigger path and its supporting state.
- Keep jumps driven by ordinary prediction requests only.

## Testing

- Not run.

## 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)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

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Release Notes:

- N/A
131ff63ce5Ben Kunkle committed on 6/22/2026, 9:22:15 PM· committed by GitHubparent037f32a
2 files changedLine totals unavailable