The original fix for #60920 cleared _OUTPUT_HISTORY in _recover_terminal_after_interrupt
to prevent the interrupt marker from being replayed on redraw. This approach:
- Discarded legitimate scrollback content unnecessarily
- Broke /redraw and Ctrl+L replay for any content after an interrupt
Instead, the interrupt marker is now printed via _cprint inside a
_suspend_output_history() context so it never enters _OUTPUT_HISTORY.
_recover_terminal_after_interrupt no longer needs to clear history — the
marker was never recorded, so _replay_output_history cannot duplicate it.
Also adds:
- _show_interrupt_marker flag to cleanly separate marker rendering from
response construction
- Focused regression tests covering the marker recording suppression,
history preservation after recovery, replay cleanliness, and flag logic
Fixes: #60941
Alli