Recover from SIGWINCH without clearing the physical screen or scrollback
buffer. The startup banner and tool summary are printed before
prompt_toolkit owns the live chrome, so they live in normal terminal
scrollback. Calling erase_screen() + \x1b[3J] on every resize removed
that UI permanently — _replay_output_history cannot reconstruct it
because the banner was never added to _OUTPUT_HISTORY.
Instead, just reset prompt_toolkit's renderer cache and invalidate so
the next incremental redraw starts from a clean slate, then let the
original on_resize handler recalculate layout for the new terminal
size. This matches the behaviour of bash/zsh/fish on SIGWINCH.
FixesNousResearch/hermes-agent#22999
vominh1919
e2b2d48610