test(deploy): cover cross-cluster rejection through the actor; note reservation false-positive at gate

src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane/AdminOperations/AdminOperationsActor.cs

@@ -85,6 +85,10 @@ public sealed class AdminOperationsActor : ReceiveActor
             // derivation, cross-cluster/namespace binding, driver-namespace compat, signal collisions,
             // …) gates the deploy. A green build in this repo does not prove the config is valid; this
             // is the last guard before a bad address space (or a non-derived EquipmentId) ships.
+            // NOTE: a BadDuplicateExternalIdentifier rejection from the reservation pre-flight can
+            // (rarely) be a false positive if an external-id reservation release has not yet been
+            // committed/visible when the snapshot is read — operators seeing a spurious one should
+            // check ExternalIdReservation state before re-submitting.
             var draft = await DraftSnapshotFactory.FromConfigDbAsync(db);
             var errors = DraftValidator.Validate(draft);
             if (errors.Count > 0)