Remove the unused TUI shutdown app command (#34553)

Remove the unconstructed `AppCommand::Shutdown` variant, its helper, and its
pending interactive replay handling.

GitOrigin-RevId: 25e8ac7ebf2498a7d70ad1625d363395a9c6f578

codex-rs/tui/src/app/pending_interactive_replay.rs

@@ -82,7 +82,6 @@ impl PendingInteractiveReplayState {
                 | AppCommand::ResolveElicitation { .. }
                 | AppCommand::RequestPermissionsResponse { .. }
                 | AppCommand::UserInputAnswer { .. }
-                | AppCommand::Shutdown
         )
     }
 
@@ -164,7 +163,6 @@ impl PendingInteractiveReplayState {
                     self.request_user_input_call_ids_by_turn_id.remove(id);
                 }
             }
-            AppCommand::Shutdown => self.clear(),
             _ => {}
         }
     }

codex-rs/tui/src/app_command.rs

@@ -90,7 +90,6 @@ pub(crate) enum AppCommand {
     SetThreadName {
         name: String,
     },
-    Shutdown,
     Review {
         target: ReviewTarget,
     },
@@ -232,11 +231,6 @@ impl AppCommand {
         Self::SetThreadName { name }
     }
 
-    #[allow(dead_code)]
-    pub(crate) fn shutdown() -> Self {
-        Self::Shutdown
-    }
-
     pub(crate) fn review(target: ReviewTarget) -> Self {
         Self::Review { target }
     }