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.Host.Tests/CentralDbTestEnvironment.cs

@@ -1,7 +1,7 @@
 namespace ZB.MOM.WW.ScadaBridge.Host.Tests;
 
 /// <summary>
-/// Host-003: <c>appsettings.Central.json</c> no longer commits database connection
+/// <c>appsettings.Central.json</c> no longer commits database connection
 /// strings — they are externalised to environment variables. Tests that exercise the
 /// full <c>Program</c> startup pipeline against the real SQL provider must therefore
 /// supply the local dev connection string the way a deployment would: via an
@@ -13,7 +13,7 @@ namespace ZB.MOM.WW.ScadaBridge.Host.Tests;
 /// <c>DOTNET_ENVIRONMENT=Central</c> without an explicit pepper env var.
 ///
 /// Also supplies <c>ScadaBridge__Database__MachineDataDb</c> so the Central-role
-/// StartupValidator preflight (reverts Host-008, REQ-HOST-3/4, M2.9 #17) does not
+/// StartupValidator preflight (a missing MachineDataDb setting) does not
 /// fail for tests that set <c>DOTNET_ENVIRONMENT=Central</c> without an explicit
 /// MachineDataDb env var.
 ///
@@ -78,6 +78,7 @@ internal sealed class CentralDbTestEnvironment : IDisposable
     /// </summary>
     private static int _liveCount;
 
+    /// <summary>Initializes a new instance of <c>CentralDbTestEnvironment</c>.</summary>
     public CentralDbTestEnvironment()
     {
         if (Interlocked.Increment(ref _liveCount) != 1)
@@ -107,6 +108,7 @@ internal sealed class CentralDbTestEnvironment : IDisposable
         Environment.SetEnvironmentVariable(JwtSigningKeyKey, JwtSigningKey);
     }
 
+    /// <summary>Releases the resources held by the test fixture.</summary>
     public void Dispose()
     {
         Environment.SetEnvironmentVariable(ConfigKey, _previousConfig);