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.Server/Configuration/IGatewayConfigurationProvider.cs

@@ -8,5 +8,6 @@ public interface IGatewayConfigurationProvider
     /// <summary>
     /// Returns the validated and effective gateway configuration.
     /// </summary>
+    /// <returns>The validated and effective gateway configuration.</returns>
     EffectiveGatewayConfiguration GetEffectiveConfiguration();
 }