docs(tests): fix CommentChecker findings across tests/ — 13,392 → 0 (repo-wide scan clean)

Comment/XML-doc changes only:
- add summaries to ~10k test methods, fixtures, fakes and helpers
  (+ <param> on theories, <returns> on async Task methods,
  <inheritdoc/> on interface implementations the checker can resolve)
- strip ~2.6k project-tracking references (WP*, P*-*, row-NN, Task N,
  #NN, Component-0NN) from comments, keeping the explanatory text;
  reword false positives in comments only
- real docs on fakes implementing BCL/library interfaces
  (IDisposable, ILogger, IOptionsMonitor, IAsyncLifetime)
- reword the last 5 src/ false positives (CWE-1236, failures-1,
  year-0001, M365)

Only non-comment edits: four one-line nested classes split across lines
so members can carry docs. Build 0 errors / 0 warnings.

tests/ZB.MOM.WW.ScadaBridge.IntegrationTests/Cluster/SiteFailoverRelayTests.cs

@@ -5,7 +5,7 @@ using ZB.MOM.WW.ScadaBridge.Communication.ClusterState;
 namespace ZB.MOM.WW.ScadaBridge.IntegrationTests.Cluster;
 
 /// <summary>
-/// Real-cluster proof for the central→site failover relay (Task 10). The unit tests in
+/// Real-cluster proof for the central→site failover relay. The unit tests in
 /// <c>SiteCommunicationActorTests</c> pin the routing and guard logic with the failover action
 /// stubbed out; this pins the part they cannot — that the shared
 /// <see cref="ClusterFailoverCoordinator"/> actually moves a SITE pair when scoped to the
@@ -17,6 +17,8 @@ namespace ZB.MOM.WW.ScadaBridge.IntegrationTests.Cluster;
 /// </summary>
 public sealed class SiteFailoverRelayTests
 {
+    /// <summary>Verifies that failing over a site pair moves the oldest node and the survivor takes over.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Failing_over_a_site_pair_moves_the_oldest_and_the_survivor_takes_over()
     {
@@ -35,6 +37,8 @@ public sealed class SiteFailoverRelayTests
         Assert.True(ActiveNodeEvaluator.SelfIsOldestUp(Akka.Cluster.Cluster.Get(f.NodeB), "site-SiteA"));
     }
 
+    /// <summary>Verifies that a site role scope matching no member is refused.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task A_site_role_scope_that_matches_no_member_is_refused()
     {