- Composite PK (user_id, track_id) already serves WHERE user_id queries;
the secondary (user_id, created_at DESC) index just amplified writes.
- ListQuarantineForUser now selects only the joined fields the SPA card
actually renders (~10 columns) rather than embedding three full structs
(~35 columns); halves wire/DB bandwidth before consumers exist.
- max(q.created_at)::timestamptz cast emits pgtype.Timestamptz instead of
interface{} so handlers can read latest_at without a type-assert.
bvandeusen
71a9bd8dee