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.Tests/Alarms/AlarmFailoverEndToEndTests.cs

@@ -32,6 +32,8 @@ public sealed class AlarmFailoverEndToEndTests
 {
     private static readonly TimeSpan WaitTimeout = TimeSpan.FromSeconds(30);
 
+    /// <summary>Verifies the alarm feed reflects each stage of a full alarmmgr-to-subtag failover and failback lifecycle.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ProviderFailoverAndFailback_FullLifecycle_ReflectedInFeed()
     {
@@ -227,6 +229,8 @@ public sealed class AlarmFailoverEndToEndTests
         await monitor.StopAsync(CancellationToken.None);
     }
 
+    /// <summary>Verifies a degraded transition cached before a new subscriber connects is replayed with its degraded flag and source provider intact.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task DegradedTransition_CachedThenReplayed_CarriesDegradedAndSourceProviderToNewSubscriber()
     {
@@ -400,10 +404,13 @@ public sealed class AlarmFailoverEndToEndTests
         public SubscribeAlarmsCommand? LastSubscribeCommand { get; private set; }
 
         /// <summary>Pushes a worker event onto the monitor's event stream.</summary>
+        /// <param name="mxEvent">The worker event to push.</param>
         public void EmitEvent(MxEvent mxEvent) =>
             _events.Writer.TryWrite(new WorkerEvent { Event = mxEvent });
 
         /// <summary>Completes once the monitor has issued its SubscribeAlarms command.</summary>
+        /// <param name="timeout">The maximum time to wait.</param>
+        /// <returns>A task that completes once the SubscribeAlarms command has been issued.</returns>
         public Task WaitForSubscribeAsync(TimeSpan timeout) => _subscribed.Task.WaitAsync(timeout);
 
         /// <inheritdoc />