Keep interrupted prompts in conversation history (#33198)

## What changed

- Leave an output-free interrupted prompt in the transcript and open a blank
  composer for the user's next instruction.
- Use the normal interruption notice for both `Esc` and `Ctrl-C` interrupts.
- Track safety-buffering prompts separately so failed retries can still restore
  the prompt, including after switching between threads.

## Testing

- Cover output-free `Esc` and `Ctrl-C` interrupts, failed safety-buffer retries,
  and restoration of safety-buffer state from thread snapshots.

GitOrigin-RevId: 30b368d00dfdb981d06d4c95ce3f252389b7917c

codex-rs/tui/src/chatwidget.rs

@@ -664,7 +664,7 @@ pub(crate) struct ChatWidget {
     // order.
     suppress_initial_user_message_submit: bool,
     input_queue: InputQueueState,
-    cancel_edit: CancelEditState,
+    safety_buffering_prompt: Option<UserMessage>,
     /// Main chat-surface bindings resolved from `tui.keymap.chat`.
     chat_keymap: ChatKeymap,
     /// Keybinding to show for popping the most-recently queued message back
@@ -787,13 +787,6 @@ pub(crate) enum InterruptedTurnNoticeMode {
     Suppress,
 }
 
-#[derive(Debug, Default)]
-struct CancelEditState {
-    prompt: Option<UserMessage>,
-    eligible: bool,
-    armed: bool,
-}
-
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub(crate) enum ReplayKind {
     ResumeInitialMessages,
@@ -1219,9 +1212,6 @@ impl ChatWidget {
     }
 
     fn add_boxed_history(&mut self, cell: Box<dyn HistoryCell>) {
-        if self.turn_lifecycle.agent_turn_running && !cell.display_lines(u16::MAX).is_empty() {
-            self.record_visible_turn_activity();
-        }
         // Keep the placeholder session header as the active cell until real session info arrives,
         // so we can merge headers instead of committing a duplicate box to history.
         let keep_placeholder_header_active = !self.is_session_configured()
@@ -1840,12 +1830,7 @@ impl ChatWidget {
     }
 
     pub(crate) fn prepare_local_op_submission(&mut self, op: &AppCommand) {
-        if let AppCommand::Interrupt { behavior } = op
-            && self.turn_lifecycle.agent_turn_running
-        {
-            if *behavior == crate::app_command::InterruptBehavior::RestorePromptIfNoOutput {
-                self.arm_cancel_edit();
-            }
+        if matches!(op, AppCommand::Interrupt) && self.turn_lifecycle.agent_turn_running {
             if let Some(controller) = self.stream_controller.as_mut() {
                 controller.clear_queue();
             }