feat(quota): add QuotaStore facade and types re-export (B/F6)

src/lib/quota/QuotaStore.ts

@@ -0,0 +1,23 @@
+/**
+ * QuotaStore.ts — Public façade for the Quota Sharing Engine.
+ *
+ * Re-exports the interface types from types.ts and the factory from
+ * storeFactory.ts so consumers have a single import point.
+ *
+ * Usage:
+ *   import { getQuotaStore } from "@/lib/quota/QuotaStore";
+ *   import type { QuotaStore, EnforceDecision } from "@/lib/quota/QuotaStore";
+ *
+ * Part of: Group B — Quota Sharing Engine (plan 22, frente F6).
+ */
+
+export type {
+  QuotaStore,
+  EnforceDecision,
+  ConsumeResult,
+  PoolUsageSnapshot,
+  EnforceInput,
+  RecordConsumptionInput,
+} from "./types";
+
+export { getQuotaStore, getQuotaStoreSync, resetQuotaStoreSingleton } from "./storeFactory";