Add IsPaused/OnPause to TrackCard, make TracksGallery controlled, and
drive the active track from PlayerService.CurrentTrack as the single
source of truth.
TrackCard, TracksGallery, DDIcons, DeepDrftPalettes (Default+Cms), DeepDrftFontLinks,
and palette CSS tokens extracted. Both hosts and DeepDrftCms reference the shared RCL.