feat(dotnet-client): operator credentials on acknowledge-alarm

Claude-Session: https://claude.ai/code/session_016J6isfcgqy4SB2RK3ZvFvT

clients/dotnet/ZB.MOM.WW.MxGateway.Client/MxGatewayClient.cs

@@ -183,24 +183,32 @@ public sealed class MxGatewayClient : IAsyncDisposable
     }
 
     /// <summary>
-    /// Acknowledges an active MXAccess alarm condition through the gateway. The
-    /// gateway authenticates the request against the API key's <c>invoke:alarm-ack</c>
-    /// scope and forwards the acknowledge to the worker's MXAccess session;
-    /// the resulting <see cref="MxStatusProxy"/> is returned in the reply.
+    /// Acknowledges an alarm as the operator. The gateway authenticates
+    /// <see cref="AcknowledgeAlarmRequest.OperatorUser"/> with
+    /// <see cref="AcknowledgeAlarmRequest.OperatorPassword"/> and writes the
+    /// comment to the alarm's AckMsg attribute, so the alarm history records
+    /// the operator. The password is redacted from any surfaced error.
     /// </summary>
-    /// <param name="request">The acknowledge request — alarm reference, comment, operator user.</param>
+    /// <param name="request">The acknowledge request: alarm reference, comment, operator credentials.</param>
     /// <param name="cancellationToken">Cancellation token for the operation.</param>
     /// <returns>The acknowledge reply with protocol + native MxStatus.</returns>
-    public Task<AcknowledgeAlarmReply> AcknowledgeAlarmAsync(
+    public async Task<AcknowledgeAlarmReply> AcknowledgeAlarmAsync(
         AcknowledgeAlarmRequest request,
         CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(request);
         ThrowIfDisposed();
 
-        return ExecuteSafeUnaryAsync(
-            token => _transport.AcknowledgeAlarmAsync(request, CreateCallOptions(token)),
-            cancellationToken);
+        try
+        {
+            return await ExecuteSafeUnaryAsync(
+                token => _transport.AcknowledgeAlarmAsync(request, CreateCallOptions(token)),
+                cancellationToken).ConfigureAwait(false);
+        }
+        catch (MxGatewayException ex) when (request.OperatorPassword.Length > 0)
+        {
+            throw MxGatewaySecretRedaction.Redacted(ex, request.OperatorPassword);
+        }
     }
 
     /// <summary>