Preserve in-flight state when restoring thread input (#33203)

## What changed

- Add an explicit restore mode for thread input snapshots and use it when replaying thread snapshots.
- Preserve the pending-steer interrupt flag alongside running-turn and queued-input state when restoring an in-flight turn.
- When in-flight state is not preserved, clear stale running flags and move pending steers ahead of already queued follow-ups while retaining their history records.

## Testing

- Expand TUI tests to cover both restoration modes, including sleep-inhibitor state, pending-steer ordering, history records, and queued submission.

GitOrigin-RevId: f4e8b2bdf065ef6c6644b7f0ea9cf32c8a9af619

codex-rs/tui/src/chatwidget.rs

@@ -427,6 +427,7 @@ use self::user_messages::QueuedUserMessage;
 use self::user_messages::ShellEscapePolicy;
 use self::user_messages::ThreadComposerState;
 pub(crate) use self::user_messages::ThreadInputState;
+pub(crate) use self::user_messages::ThreadInputStateRestoreMode;
 pub(crate) use self::user_messages::UserMessage;
 use self::user_messages::UserMessageDisplay;
 #[cfg(test)]