Scroll events of inner containers don't bubble and were filtered out by the
page-scroll-only listener — scrolling a block produced no step at all. Now
the container itself is captured (debounced per element, with its element
context, like inputs) and replayed via el.scrollTo on the resolved element;
window scrolls keep the viewport scaling. A container the replay can't find
counts as a step failure. E2E covers both: a #scroller step recorded with
its selector and the scroll observed in the replay tab (sessionStorage latch
survives the mid-replay navigation).

Co-Authored-By: Claude Code <noreply@anthropic.com>