Add dd-nav-item-collapsed CSS class toggled on child click to override the :hover/:focus-within show rules. Cleared on mouseleave so hover-to-open works normally on the next pass. Mirrors the existing CloseMobileMenu pattern.
Replaces flat RELEASES/SESSIONS/MIXES nav with ARCHIVE dropdown (PageRoute.Children, one-level cap, dual-role node). Adds /archive overview, /cuts (AlbumsView + medium filter; /albums redirects), /sessions + /sessions/{id} (hero-dominant), /mixes + /mixes/{id} (MixWaveformVisualizer full-page background). Extracts ReleaseDetailScaffold from TrackDetail (invariant trio). PersistentComponentState bridge on all new pages. Click-to-seek seam designed on MixWaveformVisualizer (inert until wired).
daniel-c-harvey