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/MxAccess/IWorkerRuntimeSession.cs

@@ -34,6 +34,7 @@ public interface IWorkerRuntimeSession : IDisposable
     /// <summary>
     /// Captures a heartbeat snapshot of the runtime state.
     /// </summary>
+    /// <returns>The current heartbeat snapshot.</returns>
     WorkerRuntimeHeartbeatSnapshot CaptureHeartbeat();
 
     /// <summary>
@@ -46,6 +47,7 @@ public interface IWorkerRuntimeSession : IDisposable
     /// <summary>
     /// Drains a pending fault from the queue, if any.
     /// </summary>
+    /// <returns>The pending fault, or <see langword="null"/> if none is queued.</returns>
     WorkerFault? DrainFault();
 
     /// <summary>