docs(src): add missing XML docs and strip tracking-ID comments

Sweep of 203 source files resolving CommentChecker findings: add
<summary>/<param>/<returns>/<inheritdoc> where missing, and remove
resolved task/issue tracking markers (Tests-NNN, Worker-NNN, Server-NNN,
Task N) from code comments. Comment/doc-only — no logic changes.
Server+Tests build clean under TreatWarningsAsErrors.

src/ZB.MOM.WW.MxGateway.Worker/Ipc/WorkerFrameWriter.cs

@@ -28,6 +28,7 @@ public sealed class WorkerFrameWriter
     /// <summary>Writes a worker envelope frame to the stream with length prefix.</summary>
     /// <param name="envelope">Worker envelope to write.</param>
     /// <param name="cancellationToken">Token to cancel the asynchronous operation.</param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     public async Task WriteAsync(
         WorkerEnvelope envelope,
         CancellationToken cancellationToken = default)