docs: strip task-tracking IDs from code comments and fill missing XML docs

Tracking IDs are review bookkeeping that rots in shipped source; the rationale they tagged is kept. Comment-only change (CommentChecker 458 -> 16 false positives).

src/ZB.MOM.WW.MxGateway.Server/Security/Audit/AuditDrainService.cs

@@ -39,12 +39,7 @@ public sealed class AuditDrainService(
     /// <summary>Upper bound on how long shutdown waits for the remaining buffered events.</summary>
     private static readonly TimeSpan ShutdownDrainCap = TimeSpan.FromSeconds(2);
 
-    /// <summary>
-    /// Bootstraps the audit table, runs one retention sweep, then attaches the drain so the
-    /// writer switches from synchronous write-through to enqueueing.
-    /// </summary>
-    /// <param name="cancellationToken">Token to observe for cancellation.</param>
-    /// <returns>A task that represents the asynchronous operation.</returns>
+    /// <inheritdoc />
     public override async Task StartAsync(CancellationToken cancellationToken)
     {
         try
@@ -64,12 +59,7 @@ public sealed class AuditDrainService(
         await base.StartAsync(cancellationToken).ConfigureAwait(false);
     }
 
-    /// <summary>
-    /// Detaches the drain (so late writes go straight to the sink) and gives the buffered
-    /// events a bounded window to reach the store.
-    /// </summary>
-    /// <param name="cancellationToken">Token to observe for cancellation.</param>
-    /// <returns>A task that represents the asynchronous operation.</returns>
+    /// <inheritdoc />
     public override async Task StopAsync(CancellationToken cancellationToken)
     {
         writer.DetachDrain();