docs: add missing XML doc comments across gateway, worker, and .NET client

Resolves 1113 documentation-completeness gaps flagged by CommentChecker
(MissingReturns, MissingInheritDoc, InheritDocMisused, MissingDoc,
MissingParam, RedundantInheritDoc) so the API surface is fully documented
and the analyzer scan is clean. Doc comments only; no code changes.

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

@@ -7,6 +7,7 @@ namespace ZB.MOM.WW.MxGateway.Client.Tests;
 public sealed class MxGatewayClientSessionTests
 {
     /// <summary>Verifies that open session attaches API key metadata and cancellation token.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task OpenSessionRawAsync_AttachesApiKeyMetadataAndCancellation()
     {
@@ -22,6 +23,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that open session returns a session with the raw open reply.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task OpenSessionAsync_ReturnsSessionWithRawOpenReply()
     {
@@ -37,6 +39,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that register builds a register command and returns server handle.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task RegisterAsync_BuildsRegisterCommandAndReturnsServerHandle()
     {
@@ -62,6 +65,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that add item 2 builds a command with the specified context.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task AddItem2Async_BuildsAddItem2CommandWithContext()
     {
@@ -87,6 +91,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that write raw builds a write command with the raw value.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task WriteRawAsync_BuildsWriteCommandWithRawValue()
     {
@@ -118,6 +123,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that write 2 raw builds a write 2 command with value and timestamp.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Write2RawAsync_BuildsWrite2CommandWithValueAndTimestamp()
     {
@@ -146,6 +152,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that subscribe bulk builds one command and returns per-item results.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task SubscribeBulkAsync_BuildsOneBulkCommandAndReturnsPerItemResults()
     {
@@ -185,6 +192,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that stream events yields events in the order received from the gateway.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task StreamEventsAsync_YieldsEventsInGatewayOrder()
     {
@@ -216,6 +224,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that close is explicit and idempotent.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task CloseAsync_IsExplicitAndIdempotent()
     {
@@ -232,6 +241,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that invoke retries safe diagnostic commands on transient RPC failure.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task InvokeAsync_RetriesSafeDiagnosticCommandOnTransientGrpcFailure()
     {
@@ -256,6 +266,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that open session does not retry on transient RPC failure.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task OpenSessionAsync_DoesNotRetryTransientGrpcFailure()
     {
@@ -269,6 +280,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that invoke does not retry write commands on transient RPC failure.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task InvokeAsync_DoesNotRetryWriteCommand()
     {
@@ -284,6 +296,7 @@ public sealed class MxGatewayClientSessionTests
     }
 
     /// <summary>Verifies that invoke helpers pass cancellation token to the transport.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task InvokeHelpers_PassCancellationTokenToTransport()
     {