The collapse feature was only half-present on the Plex page: App already passed the
shared filterCollapsed state + toggle to PlexSidebar, and PlexSidebar rendered the
CollapsedFilterRail when collapsed — but the EXPANDED PlexSidebar had no trigger, so
you could only collapse it by first collapsing on the feed page. Add the same
ChevronLeft 'Filters' collapse header the feed Sidebar has (reusing the existing
sidebar.* i18n keys). E2E-verified: collapse→rail→expand round-trips on the Plex page.
peter
2fcef981cd