docs: complete XML-doc coverage and strip internal tracking IDs from code comments

Resolve all CommentChecker findings across the gateway server, worker, tests,
and .NET client (314 -> 0 real issues): add missing <returns>/<summary>/<param>
on public and test members, convert Stream/interface overrides to <inheritdoc/>,
and remove internal task/issue tracking IDs (SEC-*, IPC-*, WRK-*, GWC-*, TST-*,
Client.Dotnet-*) from shipped code documentation while preserving the design
rationale prose. Shipped comments should not carry internal bookkeeping, and
complete XML docs keep the analyzer/TreatWarningsAsErrors gate and generated API
docs clean. The 6 remaining flags are heuristic false positives (MD5, UTC-4,
capacity-1, near-1601) left intact so real documentation is not corrupted.

Claude-Session: https://claude.ai/code/session_01DMXXvNuPekkkrTEyPNxEkW

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 reply, for chaining.</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 reply, for chaining.</returns>
     public static MxCommandReply EnsureMxAccessSuccess(this MxCommandReply reply)
     {
         ArgumentNullException.ThrowIfNull(reply);