HorizontalScrollRow takes an optional shared ScrollController so
multi-row sections (Most played: 3 rows) couple their scroll like the
web HorizontalScrollRow.svelte. Cards fall back to the synced
album-fallback.svg when coverUrl is empty.
LibraryApi wraps GET /api/home, /api/artists/{id}(/tracks),
/api/albums/{id}. dioProvider builds an authenticated dio (token
resolver reads session_token from secure storage on every request).
homeProvider, artistProvider(id), albumProvider(id) sit on top.
bvandeusen