docs: strip task-tracking IDs from code comments and fill missing XML docs

Tracking IDs are review bookkeeping that rots in shipped source; the rationale they tagged is kept. Comment-only change (CommentChecker 458 -> 16 false positives).

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/MxAccessStaSession.cs

@@ -60,8 +60,8 @@ public sealed class MxAccessStaSession : IWorkerRuntimeSession
     // the StaCommandDispatcher (so it does not inflate PendingCommandCount or perturb command dispatch
     // ordering), which means CaptureHeartbeat would otherwise see no in-flight activity during a long
     // poll and the watchdog would fault the session at the 15 s grace instead of the 75 s ceiling
-    // granted to dispatched commands. Surfacing the poll on the heartbeat closes that asymmetry
-    // (WRK-27). Volatile: written on the STA thread, read on the heartbeat thread.
+    // granted to dispatched commands. Surfacing the poll on the heartbeat closes that asymmetry.
+    // Volatile: written on the STA thread, read on the heartbeat thread.
     private volatile bool staAlarmPollInProgress;
     private bool disposed;
 
@@ -204,6 +204,7 @@ public sealed class MxAccessStaSession : IWorkerRuntimeSession
     ///     environment variable; a missing or invalid value falls back to
     ///     <see cref="MxAccessCommandExecutor.DefaultWriteCompletionTimeout"/>.
     /// </summary>
+    /// <returns>The resolved write-completion timeout.</returns>
     internal static TimeSpan ResolveWriteCompletionTimeout()
     {
         string? value = Environment.GetEnvironmentVariable(WorkerLaunchEnvironment.WriteCompletionWaitMilliseconds);
@@ -344,8 +345,8 @@ public sealed class MxAccessStaSession : IWorkerRuntimeSession
                     await staRuntime.InvokeAsync(
                         () =>
                         {
-                            // Advertise the poll to the watchdog for exactly the span of the COM call
-                            // (WRK-27): set on the STA thread immediately before the affinity check and
+                            // Advertise the poll to the watchdog for exactly the span of the COM call:
+                            // set on the STA thread immediately before the affinity check and
                             // PollOnce, clear in the finally so a heartbeat captured mid-poll reports
                             // StaCallInProgress and one captured after does not.
                             staAlarmPollInProgress = true;