Add XML documentation across gateway, worker, and .NET client

src/MxGateway.Tests/Gateway/Grpc/MxAccessGrpcMapperTests.cs

@@ -5,6 +5,7 @@ namespace MxGateway.Tests.Gateway.Grpc;
 
 public sealed class MxAccessGrpcMapperTests
 {
+    /// <summary>Verifies that command mapping clones payloads to isolate them across process boundaries.</summary>
     [Fact]
     public void MapCommand_ClonesMethodSpecificPayloadForWorkerBoundary()
     {
@@ -37,6 +38,7 @@ public sealed class MxAccessGrpcMapperTests
         Assert.NotNull(workerCommand.EnqueueTimestamp);
     }
 
+    /// <summary>Verifies that command reply mapping preserves HRESULT and status information.</summary>
     [Fact]
     public void MapCommandReply_PreservesHresultStatusesAndPayload()
     {
@@ -66,6 +68,7 @@ public sealed class MxAccessGrpcMapperTests
         Assert.Equal("denied", Assert.Single(publicReply.Statuses).DiagnosticText);
     }
 
+    /// <summary>Verifies that a missing worker reply returns a protocol violation status.</summary>
     [Fact]
     public void MapCommandReply_WhenWorkerReplyMissing_ReturnsProtocolViolationReply()
     {