The run_turn_to buffer + emit_output=false was correctly wired,
but runtime internals (child process stderr, tokio tracing, or
unstructured error paths) can still write to the real terminal fd.
Added a crossterm Clear(All) + MoveTo(0,0) after each turn to wipe
any stdout debris that may have landed on the alternate screen,
followed by a full TUI redraw to re-render both panes cleanly.
This is the belt-and-suspenders approach: buffer captures what we can,
screen clear catches what we can't.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>