The footer named "↑↓ PgUp/PgDn scroll" unconditionally, even on a tall
terminal where the whole overview fits and those keys do nothing. Gate the
scroll atom on the body actually being taller than its viewport, so Esc is
the only key advertised when there is nothing to scroll.
Add a reusable Screen.content_overflows predicate (from the metrics the
frame already records each paint) for the pattern, so any scrolling screen
can gate its footer the same way.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Jean-Pierre MartineauandClaude Opus 4.8
8daf3f1294