Add Vim buffer jump motions (#40958)

## What changed

- Add `gg` and `G` motions to jump to the first and last buffer lines.
- Support the motions with delete, change, and yank operators, including dot-repeat for edits.
- Expose normal-mode and operator-motion bindings in the configurable keymap while preserving conflicting user bindings.

## Testing

- Cover buffer jumps, operator combinations, repeat behavior, chord routing, and custom remapping.

GitOrigin-RevId: 24a9178cf7964053aaf9a8cd268c5434dda0778e

codex-rs/tui/src/keymap_setup.rs

@@ -564,7 +564,8 @@ pub(crate) fn active_binding_specs(
     context: &str,
     action: &str,
 ) -> Result<Vec<String>, String> {
-    if let Some(action_id) = keymap_action_id(context, action)
+    let action_id = keymap_action_id(context, action);
+    if let Some(action_id) = action_id
         && let Some(specs) = runtime_keymap.chords.configured_specs(action_id)
     {
         return Ok(specs.to_vec());
@@ -573,6 +574,16 @@ pub(crate) fn active_binding_specs(
     let bindings = bindings_for_action(runtime_keymap, context, action).ok_or_else(|| {
         format!("Unknown keymap action `{context}.{action}`. Reopen /keymap and choose an action.")
     })?;
+    if let Some(action_id) = action_id
+        && let Some(crate::key_hint::ShortcutHint::Chord { prefix, completion }) =
+            runtime_keymap.chords.primary_hint(action_id, bindings)
+    {
+        return Ok(vec![format!(
+            "{} {}",
+            binding_to_config_key_spec(prefix)?,
+            binding_to_config_key_spec(completion)?
+        )]);
+    }
     bindings
         .iter()
         .map(|binding| binding_to_config_key_spec(*binding))
@@ -1037,6 +1048,15 @@ mod tests {
     #[test]
     fn picker_unbound_tab_lists_default_unbound_actions() {
         let runtime = RuntimeKeymap::defaults();
+        for (context, action) in [
+            ("vim_normal", "jump_top"),
+            ("vim_operator", "motion_jump_top"),
+        ] {
+            assert_eq!(
+                active_binding_specs(&runtime, context, action).expect("native Vim chord"),
+                ["g g"]
+            );
+        }
         let params = build_keymap_picker_params(&runtime, &TuiKeymap::default());
         let unbound_tab = selection_tab(&params, KEYMAP_UNBOUND_TAB_ID);