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/MxGatewayClientAlarmsTests.cs

@@ -12,6 +12,7 @@ namespace ZB.MOM.WW.MxGateway.Client.Tests;
 public sealed class MxGatewayClientAlarmsTests
 {
     /// <summary>AcknowledgeAlarmAsync records request and returns reply.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task AcknowledgeAlarmAsync_RecordsRequestShapeAndReturnsReply()
     {
@@ -48,6 +49,7 @@ public sealed class MxGatewayClientAlarmsTests
     }
 
     /// <summary>AcknowledgeAlarmAsync honors cancellation.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task AcknowledgeAlarmAsync_HonorsCancellation()
     {
@@ -72,6 +74,7 @@ public sealed class MxGatewayClientAlarmsTests
     }
 
     /// <summary>AcknowledgeAlarmAsync maps unauthenticated RPC exception to typed exception.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task AcknowledgeAlarmAsync_MapsUnauthenticated_RpcException_ToTypedException()
     {
@@ -97,6 +100,7 @@ public sealed class MxGatewayClientAlarmsTests
     }
 
     /// <summary>QueryActiveAlarmsAsync streams enqueued snapshots.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task QueryActiveAlarmsAsync_StreamsEnqueuedSnapshots()
     {
@@ -122,6 +126,7 @@ public sealed class MxGatewayClientAlarmsTests
     }
 
     /// <summary>QueryActiveAlarmsAsync passes filter prefix.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task QueryActiveAlarmsAsync_PassesFilterPrefix()
     {
@@ -142,6 +147,7 @@ public sealed class MxGatewayClientAlarmsTests
     }
 
     /// <summary>QueryActiveAlarmsAsync honors cancellation during enumeration.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task QueryActiveAlarmsAsync_HonorsCancellationDuringEnumeration()
     {