#4584 (fixes#4295): scroll re-pin requires deliberate downward intent (deltaY<-30 unpin
threshold, re-pin only if not user-unpinned OR bottomDistance<=80, reset counter) so reading
mid-stream isn't hijacked back to bottom. ui.js only + 5 scroll-regression tests (4 existing
assertions adjusted, all green; new test_issue4295_scroll_pin_reentry).
#4583 (fixes#4553): mobile transcript overflow-x:hidden + max-width:100% + word-break so wide
content can't pan sideways. style.css only + own test. Disjoint files. 32 scroll-family tests pass.
Co-authored-by: nesquena-hermes <agent@nesquena-hermes>
Co-authored-by: rodboev <rodboev@users.noreply.github.com>
