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/GatewayOptionsValidator.cs

@@ -9,11 +9,7 @@ public sealed class GatewayOptionsValidator : OptionsValidatorBase<GatewayOption
     private const int MinimumMaxMessageBytes = 1024;
     private const int MaximumMaxMessageBytes = 256 * 1024 * 1024;
 
-    /// <summary>
-    /// Validates gateway configuration options.
-    /// </summary>
-    /// <param name="builder">The accumulator to record failures on.</param>
-    /// <param name="options">Gateway options to validate.</param>
+    /// <inheritdoc />
     protected override void Validate(ValidationBuilder builder, GatewayOptions options)
     {
         ValidateAuthentication(options.Authentication, builder);