R5.7: Gitea #1, ElyShow's slide strip scrolls with the wheel; R1 PASS

The strip's list sat in a ContextMenu host with no size, so it grew
with its content and never overflowed. The host now fills its column,
as ElyPDF's do; a 24-slide test wheels to the last slide.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/ely-show/src/tests.rs

@@ -18,6 +18,7 @@ mod play_more;
 mod play_time;
 mod review;
 mod slides;
+mod strip;
 
 /// An unrendered Deck over a fresh worker, if LOK exists.
 pub(super) fn deck(cx: &mut TestAppContext, dir: &Path) -> Option<Entity<Deck>> {