Merge feat/erp-inventar-export: read-only inventory mirror for ERPNext

Brings the ERPNext inventory export (T8) into main after its review:
strict seit format, settle window on the DB clock, BatchMovement
(createdAt, id) index, one scope per new API key and the failed-attempt
lockout on the shared throttler storage. Conflicts resolved in the
permission catalog (System and ERP-Anbindung groups) and ARCHITECTURE.md
(lockout is Annahme 30).

Gates on the merged state: backend lint, typecheck, 1909 unit, 471 e2e,
build, no schema drift; frontend 929 tests, lint, typecheck, build.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Backend/prisma/schema.prisma

@@ -1210,6 +1210,8 @@ model BatchMovement {
   @@index([productionBatchId])
   @@index([rawMaterialLotId])
   @@index([shopRequestId])
+  // ERP-Export /bewegungen: sortiert und blättert nach (createdAt, id).
+  @@index([createdAt, id])
 }
 
 enum ShopStockRequestKind {