refactor(tests): Add strict type hints to fifth batch of test files

tests/test_gui2_performance.py

@@ -11,7 +11,7 @@ from api_hook_client import ApiHookClient
 # Session-wide storage for comparing metrics across parameterized fixture runs
 _shared_metrics = {}
 
-def test_performance_benchmarking(live_gui):
+def test_performance_benchmarking(live_gui: tuple) -> None:
  """
     Collects performance metrics for the current GUI script (parameterized as gui.py and gui_2.py).
     """