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/MxCommandReplyExtensions.cs

@@ -7,6 +7,7 @@ public static class MxCommandReplyExtensions
 {
     /// <summary>Validates that the reply has a successful protocol status (Ok or MxAccessFailure), throwing a gateway exception if not.</summary>
     /// <param name="reply">The command reply to check.</param>
+    /// <returns>The same <paramref name="reply"/> for fluent chaining when validation passes.</returns>
     public static MxCommandReply EnsureProtocolSuccess(this MxCommandReply reply)
     {
         ArgumentNullException.ThrowIfNull(reply);
@@ -24,6 +25,7 @@ public static class MxCommandReplyExtensions
 
     /// <summary>Validates that the reply indicates MXAccess success (no HResult or status failures), throwing MxAccessException if not.</summary>
     /// <param name="reply">The command reply to check.</param>
+    /// <returns>The same <paramref name="reply"/> for fluent chaining when validation passes.</returns>
     public static MxCommandReply EnsureMxAccessSuccess(this MxCommandReply reply)
     {
         ArgumentNullException.ThrowIfNull(reply);