Closes audit #8 first wave. New shared widget wraps Material3's
PullToRefreshBox with isRefreshing state managed internally; consumers
pass a suspend onRefresh that the wrapper awaits before hiding the
indicator (no heuristic delays).
ViewModel pattern: refresh() now returns Job so the screen can
`.join()` it from the wrapper. Trivial change — adding `: Job =`
between the function signature and the existing viewModelScope.launch
body. Existing fire-and-forget callers continue to work since they
discard the return value.
Wired into HomeScreen, AlbumDetailScreen, ArtistDetailScreen.
Library tabs + detail / list / admin screens follow in next commits.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
bvandeusen
e6e4f6dcf1