#4644: close mobile sidebar drawer after a rail-click panel switch (was left open).
#4645: animate drawer open/close with transform:translateX instead of left offset.
Disjoint product files (panels.js vs style.css); both add tests to test_mobile_layout.py
in distinct functions (no conflict). Mobile-only, desktop unaffected. 60 mobile-layout
tests pass. Code byte-faithful from PR heads.
Co-authored-by: nesquena-hermes <agent@nesquena-hermes>
Co-authored-by: franksong2702 <franksong2702@users.noreply.github.com>