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

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

clients/dotnet/ZB.MOM.WW.MxGateway.Client.Tests/MxGatewayClientAlarmsTests.cs

@@ -36,6 +36,8 @@ public sealed class MxGatewayClientAlarmsTests
             AlarmFullReference = "Tank01.Level.HiHi",
             Comment = "investigating",
             OperatorUser = "alice",
+            OperatorPassword = "pw-secret",
+            OperatorDomain = "CORP",
         });
 
         Assert.Equal(ProtocolStatusCode.Ok, reply.ProtocolStatus.Code);
@@ -45,9 +47,35 @@ public sealed class MxGatewayClientAlarmsTests
         Assert.Equal("Tank01.Level.HiHi", call.Request.AlarmFullReference);
         Assert.Equal("investigating", call.Request.Comment);
         Assert.Equal("alice", call.Request.OperatorUser);
+        Assert.Equal("pw-secret", call.Request.OperatorPassword);
+        Assert.Equal("CORP", call.Request.OperatorDomain);
         Assert.Equal("Bearer test-api-key", call.CallOptions.Headers?.GetValue("authorization"));
     }
 
+    /// <summary>AcknowledgeAlarmAsync redacts the operator password from a failing call's message.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
+    [Fact]
+    public async Task AcknowledgeAlarmAsync_FailureMessage_DoesNotContainOperatorPassword()
+    {
+        FakeGatewayTransport transport = CreateTransport();
+
+        // The real transport maps RpcException to MxGatewayException using the status
+        // detail; the fake passes exceptions verbatim, so enqueue the mapped shape.
+        transport.AcknowledgeAlarmExceptions.Enqueue(new MxGatewayException("boom pw-secret"));
+        await using MxGatewayClient client = CreateClient(transport);
+
+        MxGatewayException ex = await Assert.ThrowsAsync<MxGatewayException>(
+            () => client.AcknowledgeAlarmAsync(new AcknowledgeAlarmRequest
+            {
+                AlarmFullReference = "Tank01.Level.HiHi",
+                OperatorUser = "alice",
+                OperatorPassword = "pw-secret",
+            }));
+
+        Assert.DoesNotContain("pw-secret", ex.Message);
+        Assert.Contains("boom", ex.Message);
+    }
+
     /// <summary>AcknowledgeAlarmAsync honors cancellation.</summary>
     /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]