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);

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();
 }

src/ZB.MOM.WW.MxGateway.Server/Configuration/SessionOptions.cs

@@ -33,7 +33,7 @@ public sealed class SessionOptions
     ///     external subscriber, so a session whose only remaining subscriber is the dashboard
     ///     mirror still enters detach-grace. A value of <c>0</c> disables retention: the
     ///     session reverts to the original behavior of lingering only until its normal lease
-    ///     expires. The reconnect/replay itself is implemented separately (Task 12); this
+    ///     expires. The reconnect/replay itself is implemented separately; this
     ///     option controls retention and expiry only.
     /// </summary>
     /// <remarks>