Introduces shared seams for paginated views, D-pad reorder, media control
routing, async singletons and the device method channel, then points the
open-coded copies at them.
Also removes unused models and duplicated provider/server plumbing, folds
the twice-implemented artifact store in the server, and factors the
repeated Flutter toolchain prologue in CI into a composite action.
Un-gates music libraries; adds CardShape.square plumbing (circular
artists), artists/albums/tracks browse groupings with per-grouping
sorts, audio playlists tab, artist + album detail screens with dpad
track rows, music context-menu actions, and a stub MusicPlaybackService
seam for the upcoming engine.
Poster images are decorative (the card exposes one merged node), and
the default per-child AutomaticKeepAlive/_SelectionKeepAlive/
IndexedSemantics wrappers are inert here — no keep-alive clients or
SelectionArea exist. The semantics phase ran ~9ms every frame on TV
devices with an accessibility service; it scales with node count.
Replace duplicated focusable action button pattern across 8 screens with
a shared FocusableActionBar widget that handles focus nodes, D-pad
navigation, back key, and focus decoration automatically.
edde746