[CLI] macOS question prompt advertises unusable Alt+Up shortcut

What version of Codex CLI is running?

CLI version not available; source checkout based on openai/codex main at a592c38c16

What subscription do you have?

Not applicable — source-level bug report

Which model were you using?

Not applicable

What platform is your computer?

Darwin 25.2.0 arm64 arm (macOS)

What terminal emulator and version are you using (if applicable)?

iTerm2 3.6.11; no multiplexer

Codex doctor report

Not available — this was confirmed by source inspection; no installed CLI doctor report was available.

What issue are you seeing?

When Codex is waiting for an async question, the collapsed question menu displays Alt+Up as the shortcut to answer or navigate. On macOS, that chord is commonly intercepted by the terminal or OS and is not reliably delivered, so the displayed control is unusable. The same shortcut is also used for editing the most recently queued message.

Root cause:

tui/src/chatwidget.rs selects Alt+Up for TerminalName::Iterm2 when no multiplexer is detected. That selected hint is propagated to the async-question footer, so the UI renders Alt+Up even though macOS users need the existing Shift+Left fallback path.

Proposed fix:

Select Shift+Left for the default chat.edit_queued_message hint on macOS, while continuing to accept Alt+Up as a compatibility binding and preserving explicit tui.keymap.chat.edit_queued_message configuration.

I implemented and locally tested this candidate fix in a clean checkout; the repository's contribution guidelines ask external contributors to submit issues rather than pull requests.

What steps can reproduce the bug?

1. Run the Codex CLI on macOS in iTerm2.
2. Start a task that asks an async question.
3. Leave the question menu collapsed.
4. Observe the footer hint: Alt+Up to answer.
5. Press Alt+Up; in macOS/iTerm2 this chord may be intercepted or not delivered, so the question navigation or answer editor does not open reliably.

What is the expected behavior?

The prompt should show a shortcut that is reliably delivered by macOS terminal environments, such as Shift+Left, and pressing it should move to the question or answer editor. The displayed hint should match the active key binding.

Additional information

Confirmed in the source:

• The default edit_queued_message action includes Alt+Up and Shift+Left.
• iTerm2 without tmux selects Alt+Up as the displayed hint on macOS.
• The async-question footer uses that selected hint.

A local candidate changes macOS default selection to Shift+Left, keeps Alt+Up as a compatibility binding, and updates regression tests and UI snapshots. Focused tests pass, and Rust formatting checks pass.

Environment: iTerm2 3.6.11 on Darwin 25.2.0 arm64.

The relevant selection is in tui/src/chatwidget.rs; start there and inspect the regression tests and UI snapshots mentioned in the report. Verify that macOS displays Shift+Left while Alt+Up remains accepted and explicit tui.keymap.chat.edit_queued_message configuration is preserved, then run the focused tests and Rust formatting checks.