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

Closes #54419

Release Notes:

- Fixed Agent menu shortcut context handling so Alt-Shift-L consistently
resolves to Rules (and displays correctly) when the Toggle Agent Menu is
open, while preserving existing global/context-specific shortcuts such
as Language Servers and onboarding bindings outside Agent menu context.

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Co-authored-by: Danilo Leal <daniloleal09@gmail.com>
Co-authored-by: Danilo Leal <67129314+danilo-leal@users.noreply.github.com>