refactor(test): wrap live_gui subprocess in _LiveGuiHandle class

tests/test_live_gui_filedialog_regression.py

@@ -34,7 +34,9 @@ def test_live_gui_project_settings_opens_without_filedialog_crash(live_gui) -> N
  5. Verifies no AttributeError was logged (the bug would print to
     the GUI's stderr, which the live_gui fixture captures to a log)
  """
- process, gui_script = live_gui
+ handle = live_gui
+ process = handle.process
+ gui_script = handle.gui_script
  client = ApiHookClient()
 
  log_path = Path(f"logs/{Path(gui_script).name.replace('.', '_')}_test.log")