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.Contracts/GatewayContractInfo.cs

@@ -23,7 +23,7 @@ public static class GatewayContractInfo
     /// <c>ZB.MOM.WW.MxGateway.IntegrationTests.LiveMxAccessFactAttribute</c> and
     /// <c>ZB.MOM.WW.MxGateway.Worker.Tests.TestSupport.LiveMxAccessFactAttribute</c>
     /// so any future opt-in tweak does not silently leave one project
-    /// behind — see Worker.Tests-025.
+    /// behind.
     /// </summary>
     public const string LiveMxAccessOptInVariableName = "MXGATEWAY_RUN_LIVE_MXACCESS_TESTS";
 }