feat(alarms): carry transition Kind on AlarmEventArgs; Galaxy populates it (Phase B WS-1)

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

@@ -71,6 +71,12 @@ public sealed record AlarmAcknowledgeRequest(
 ///     <c>Diagnostics</c>). Maps to OPC UA <c>ConditionClassName</c> downstream when
 ///     a class mapping is configured. Null when the upstream path doesn't carry it.
 /// </param>
+/// <param name="Kind">
+///     The alarm transition kind (raise / acknowledge / clear / retrigger). Lets a
+///     consumer derive OPC UA Part 9 active/ack state without inferring it from
+///     other fields. <see cref="AlarmTransitionKind.Unspecified"/> when the upstream
+///     path doesn't surface a distinct kind.
+/// </param>
 public sealed record AlarmEventArgs(
     IAlarmSubscriptionHandle SubscriptionHandle,
     string SourceNodeId,
@@ -81,7 +87,15 @@ public sealed record AlarmEventArgs(
     DateTime SourceTimestampUtc,
     string? OperatorComment = null,
     DateTime? OriginalRaiseTimestampUtc = null,
-    string? AlarmCategory = null);
+    string? AlarmCategory = null,
+    AlarmTransitionKind Kind = AlarmTransitionKind.Unspecified);
 
 /// <summary>Mirrors the <c>NodePermissions</c> alarm-severity enum in <c>docs/v2/acl-design.md</c>.</summary>
 public enum AlarmSeverity { Low, Medium, High, Critical }
+
+/// <summary>
+///     Kind of alarm state change carried by <see cref="AlarmEventArgs.Kind"/>, letting a
+///     consumer derive OPC UA Part 9 active/ack state. Mirrors the driver-side
+///     transition-kind enums (e.g. Galaxy's <c>GalaxyAlarmTransitionKind</c>).
+/// </summary>
+public enum AlarmTransitionKind { Unspecified = 0, Raise, Acknowledge, Clear, Retrigger }