worker(alarms): advise ack-comment subtag so the ack write targets an active MXAccess item

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/SubtagAlarmConsumer.cs

@@ -78,10 +78,15 @@ public sealed class SubtagAlarmConsumer : IMxAccessAlarmConsumer
     }
 
     /// <summary>
-    ///     Advises every observable alarm subtag (active / acked / priority —
-    ///     the ack-comment subtag is a write-only target and is not advised)
-    ///     and begins listening for value changes. The <paramref name="subscription"/>
-    ///     expression is ignored: the subtag set is fixed by the watch list.
+    ///     Advises every alarm subtag (active / acked / priority, plus the
+    ///     ack-comment subtag) and begins listening for value changes. The
+    ///     ack-comment subtag is advised so it is an active MXAccess item by the
+    ///     time <see cref="AcknowledgeByName"/> writes it — MXAccess rejects a
+    ///     write to an added-but-not-advised item with E_INVALIDARG (confirmed
+    ///     against live MXAccess). Its value changes carry no transition (the
+    ///     state machine ignores addresses it does not map to active/acked).
+    ///     The <paramref name="subscription"/> expression is ignored: the subtag
+    ///     set is fixed by the watch list.
     /// </summary>
     /// <param name="subscription">The subscription expression (unused in subtag mode).</param>
     public void Subscribe(string subscription)
@@ -97,6 +102,7 @@ public sealed class SubtagAlarmConsumer : IMxAccessAlarmConsumer
             AddIfNotEmpty(addresses, target.ActiveSubtag);
             AddIfNotEmpty(addresses, target.AckedSubtag);
             AddIfNotEmpty(addresses, target.PrioritySubtag);
+            AddIfNotEmpty(addresses, target.AckCommentSubtag);
         }
 
         source.Advise(addresses);