fix: remove dead SetSessionContext and update tests to use SetMessageBus

SetSessionContext(IMessageBus, SessionUid) was no longer called from
production code. Remove it and update HtmlReporterTests to call
SetMessageBus(bus) directly instead.

MTP auto-registers IDataConsumer via AddTestSessionLifetimeHandler, so
no AddDataConsumer registration is needed for HtmlReporter (adding one
would cause a "Consumer registered two time" crash).

TUnit.Engine.Tests/HtmlReporterTests.cs

@@ -50,8 +50,7 @@ public async Task PublishArtifactAsync_Publishes_SessionFileArtifact_When_Sessio
         // Arrange
         var reporter = new HtmlReporter(new MockExtension());
         var bus = new CapturingMessageBus();
-        var sessionUid = new Microsoft.Testing.Platform.TestHost.SessionUid("test-session-1");
-        reporter.SetSessionContext(bus, sessionUid);
+        reporter.SetMessageBus(bus);
 
         var tempFile = Path.GetTempFileName();
         try
@@ -92,8 +91,7 @@ public async Task PublishArtifactAsync_Is_NoOp_When_File_Does_Not_Exist()
     {
         var reporter = new HtmlReporter(new MockExtension());
         var bus = new CapturingMessageBus();
-        var sessionUid = new Microsoft.Testing.Platform.TestHost.SessionUid("test-session-2");
-        reporter.SetSessionContext(bus, sessionUid);
+        reporter.SetMessageBus(bus);
 
         await reporter.PublishArtifactAsync("/nonexistent/path/report.html", CancellationToken.None);
 

TUnit.Engine/Reporters/Html/HtmlReporter.cs

@@ -186,11 +186,6 @@ internal void SetMessageBus(IMessageBus messageBus)
         _messageBus = messageBus;
     }
 
-    internal void SetSessionContext(IMessageBus messageBus, SessionUid sessionUid)
-    {
-        _messageBus = messageBus;
-    }
-
     private ReportData BuildReportData()
     {
         var assemblyName = Assembly.GetEntryAssembly()?.GetName().Name ?? "TestResults";