Wires sync.LogChange into the library mutation sites so /api/library/sync
reflects upserts and deletes.
Architectural pivot: LogChange's signature is now (ctx, dbq.DBTX, ...) so
it works with both *pgxpool.Pool and pgx.Tx. The scanner doesn't run
mutations in explicit transactions, so it pool-binds; delete.go matches.
Tx-bound callers (likes/playlists in subsequent commits) keep atomicity.
Also: sync.FormatUUID centralizes the pgtype.UUID → canonical string
conversion that both the scanner and the sync handler need; library_sync.go
now uses it instead of a local copy.
Best-effort logging on scanner failures (Warn, don't fail the scan): a
LogChange error after a successful upsert is rare and self-healing — the
next scan that touches the entity re-emits the change.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Returns batched upserts + deletes since the supplied cursor. Empty cursor
returns full snapshot; subsequent calls pull deltas. Per-user entities
(likes, playlists) are scoped to the authed user. Composite-key entities
(likes, playlist_tracks) use stable string ids encoded by sync.EncodeLikeID
/ sync.EncodePlaylistTrackID.
Behavior:
204 No Content - no changes since cursor
200 OK - JSON syncResponse {cursor, upserts, deletes}
410 Gone - cursor older than oldest log row; client must reset
401 / 500 - standard envelope errors
Adds sqlc queries GetAlbumsByIDs, GetTracksByIDs, GetPlaylistsByIDs to
mirror the existing GetArtistsByIDs.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>