Harry Bayliss
24c8183832
Typing into a focused child while its emulator viewport was scrolled up left the keystroke heading to the PTY but the input box invisible below the visible region — it looked like typing did nothing. processStdin's flushForward now sets pendingViewportBottom whenever bytes are actually injected, so the existing post-loop handler snaps the viewport and repaints. Wheel events and Ctrl-B paths are untouched: both are intercepted before reaching forward, so wheel still scrolls into history and Ctrl-B is still the explicit escape hatch. Only bytes that would actually reach the child PTY trigger the snap.