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>
bvandeusen
9bf4b504b3