feat(alarms): AlarmAcknowledgeRequest carries OperatorUser; Galaxy/ScriptedAlarmSource honor it [H6b]

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs

@@ -41,10 +41,15 @@ public interface IAlarmSubscriptionHandle
 }
 
 /// <summary>One alarm acknowledgement in a batch.</summary>
+/// <param name="SourceNodeId">Driver-side identifier for the alarm source.</param>
+/// <param name="ConditionId">Stable id correlating raise / ack / clear of the same condition.</param>
+/// <param name="Comment">Operator-supplied comment forwarded to the upstream alarm system.</param>
+/// <param name="OperatorUser">Authenticated principal performing the ack; null on the raw/non-OPC-UA path.</param>
 public sealed record AlarmAcknowledgeRequest(
     string SourceNodeId,
     string ConditionId,
-    string? Comment);
+    string? Comment,
+    string? OperatorUser = null);
 
 /// <summary>Event payload for <see cref="IAlarmSource.OnAlarmEvent"/>.</summary>
 /// <param name="SubscriptionHandle">Subscription this event belongs to.</param>