MetadataPrefetcher gains warmAlbums(ids) / warmArtists(ids) public
methods so callers can fan out drift-cache warm-ups for whatever
collection just landed.
Wired into:
- Library Artists tab — warms first 8 artists from the page on every
data emit (initial + paginate + refresh).
- Library Albums tab — same for first 8 albums.
- Artist detail album grid — warms first 8 albums from the artist's
album list as soon as it loads, so tapping into any of them is a
drift hit.
Hard-cap of 8 per call (same as the home prefetch). Set spans across
calls aren't deduped at this layer because providers themselves
short-circuit on cached values.
Also instrument the artist-detail play button: try/catch around the
artistTracksProvider read + playTracks call, snackbar on
empty-tracks or thrown-error so silent failures stop being silent.
The current behavior was an early return on tracks.isEmpty with no
visible feedback.
Across-the-board sluggishness was every cold-cache tap doing one
network round trip while the user waits. SWR helps on re-visits but
the first time you tap a tile from home you eat the latency.
MetadataPrefetcher listens to homeProvider. When /api/home returns,
it fires fire-and-forget reads on albumProvider + artistProvider for
the top-N items in each home section (recently added, rediscover,
most played, last played). Each provider read triggers the existing
cold-cache path, which writes to drift. By the time the user
actually taps a tile, it's already a drift hit and the detail
screen renders instantly.
Cap N=8 per section (covers what's visible on a typical phone
without scrolling). Set spans dedupe across sections so popular
artists don't get fetched five times. Errors are swallowed — a
failed prefetch is silent and the tile falls back to its on-tap
fetch behavior.
Wired alongside the existing audio prefetcher in app.dart's
postFrameCallback.