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/Sta/StaMessagePump.cs

@@ -43,6 +43,7 @@ public sealed class StaMessagePump
     }
 
     /// <summary>Pumps and dispatches all pending Windows messages, returning the count processed.</summary>
+    /// <returns>The number of messages pumped and dispatched.</returns>
     public int PumpPendingMessages()
     {
         int pumpedMessages = 0;