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.NotificationOutbox.Tests/OutboxRepositorySubstitute.cs

@@ -22,6 +22,7 @@ namespace ZB.MOM.WW.ScadaBridge.NotificationOutbox.Tests;
 internal static class OutboxRepositorySubstitute
 {
     /// <summary>Creates a substitute whose writes report that the row was found.</summary>
+    /// <returns>A substitute outbox repository whose writes report the row as found.</returns>
     public static INotificationOutboxRepository Healthy()
     {
         var repository = Substitute.For<INotificationOutboxRepository>();