## Summary
Extend Ctrl+n/Ctrl+p navigation support to selection popups (model
picker, approval mode, etc.)
This is a follow-up to #7530, which added Ctrl+n/Ctrl+p navigation to
the textarea.
The same keybindings were missing from `ListSelectionView`, causing
inconsistent behavior
when navigating selection popups.
## Related
- #7530 - feat(tui): map Ctrl-P/N to arrow navigation in textarea
## Changes
- Added Ctrl+n as alternative to Down arrow in selection popups
- Added Ctrl+p as alternative to Up arrow in selection popups
- Added unit tests for the new keybindings
## Test Plan
- [x] `cargo test -p codex-tui list_selection_view` - all tests pass
- [x] Manual testing: verified Ctrl+n/p navigation works in model
selection popup
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Co-authored-by: Eric Traut <etraut@openai.com>
