Edit queued messages with Vim history-up (#38907)

## What changed

- When the composer is empty in Vim normal mode, make the configured history-up binding restore the latest queued follow-up for editing.
- Remove the restored message from the queue so submitting the edited version replaces it instead of creating a duplicate.
- Preserve normal history navigation when the composer has text or a popup is active, and honor remapped Vim bindings.

## Testing

- Add TUI tests covering repeated edit-and-requeue cycles and a remapped history-up binding.

GitOrigin-RevId: 0b04dd964d3fc6fdcd10712aa4d5fd81cbbd2255

codex-rs/tui/src/bottom_pane/chat_composer.rs

@@ -44,6 +44,11 @@
 //! - Persistent cross-session history (text-only; no element ranges or attachments).
 //! - Local in-session history (full text + text elements + local/remote image attachments).
 //!
+//! Before composer history handles Vim-normal history-up, `ChatWidget` restores the latest queued
+//! follow-up when the composer is empty and no popup is active. It removes the message from the
+//! queue before placing it in the composer, so editing and requeuing it replaces the prior
+//! revision instead of creating duplicates.
+//!
 //! When recalling a local entry, the composer rehydrates text elements and both attachment kinds
 //! (local image paths + remote image URLs).
 //! When recalling a persistent entry, only the text is restored.

codex-rs/tui/src/bottom_pane/mod.rs

@@ -1222,8 +1222,12 @@ impl BottomPane {
         popup_consts::standard_popup_hint_line_for_keymap(&self.keymap.list)
     }
 
+    pub(crate) fn runtime_keymap(&self) -> &RuntimeKeymap {
+        &self.keymap
+    }
+
     pub(crate) fn list_keymap(&self) -> crate::keymap::ListKeymap {
-        self.keymap.list.clone()
+        self.runtime_keymap().list.clone()
     }
 
     /// Replace one or more active views whose IDs are in `view_ids` with a