Read the active index under the player lock and remove stale entries
only when the indexed instance id still matches, preventing concurrent
get/complete/reissue from dropping a newer active pointer.
Lock idempotency keys alongside row ids in TryAppend so concurrent
duplicate keys cannot both succeed; return true from TryClearInstance
when the row is absent to match Postgres idempotent DELETE behavior.
Nest player and instance locks in TryCreateActive, TryMarkComplete, and
TryClearInstance so concurrent create and complete cannot leave a stale
active index or mismatched snapshot.
Durable per-player contract instances (one active) and append-only
outcome audit rows, mirroring NEO-116/135 store patterns with V011/V012
migrations, AAA tests, README docs, and Bruno health smoke.
VinPropane