perf(engine): skip tracked object graph rediscovery

TUnit.Engine/Services/ObjectLifecycleService.cs

@@ -250,7 +250,9 @@ private async Task InitializeTrackedObjectsAsync(TestContext testContext, Cancel
             var tasks = new List<Task>(objectsAtLevel.Count);
             foreach (var obj in objectsAtLevel)
             {
-                tasks.Add(InitializeObjectWithSpanAsync(obj, testContext, cancellationToken));
+                // Tracked objects were discovered before execution and are already
+                // ordered deepest-first, so nested graph traversal would be redundant.
+                tasks.Add(InitializeObjectOnlyWithSpanAsync(obj, testContext, cancellationToken));
             }
 
             if (tasks.Count > 0)
@@ -268,12 +270,20 @@ private async Task InitializeTrackedObjectsAsync(TestContext testContext, Cancel
 
     /// <summary>
     /// Initializes an object and its nested objects, wrapped in a scope-aware OpenTelemetry span.
+    /// Used for objects outside the tracked graph, such as the test class instance.
     /// </summary>
     private async Task InitializeObjectWithSpanAsync(object obj, TestContext testContext, CancellationToken cancellationToken)
     {
-        // First initialize nested objects depth-first
         await InitializeNestedObjectsForExecutionAsync(obj, cancellationToken);
+        await InitializeObjectOnlyWithSpanAsync(obj, testContext, cancellationToken);
+    }
 
+    /// <summary>
+    /// Initializes only the supplied object, wrapped in a scope-aware OpenTelemetry span.
+    /// Callers that use this directly must initialize nested dependencies first.
+    /// </summary>
+    private async Task InitializeObjectOnlyWithSpanAsync(object obj, TestContext testContext, CancellationToken cancellationToken)
+    {
 #if NET
         var sharedType = TraceScopeRegistry.GetSharedType(obj);
         var activitySource = TUnitActivitySource.GetSourceForSharedType(sharedType);