chore(tech-debt): Finalize gui_2.py cleanup and test suite discipline

tests/test_gui_streaming.py

@@ -2,22 +2,6 @@ import pytest
 from unittest.mock import patch
 from gui_2 import App
 
-@pytest.fixture
-def app_instance():
- with (
-  patch('gui_2.load_config', return_value={'ai': {}, 'projects': {}}),
-  patch('gui_2.save_config'),
-  patch('gui_2.project_manager'),
-  patch('gui_2.session_logger'),
-  patch('gui_2.immapp.run'),
-  patch.object(App, '_load_active_project'),
-  patch.object(App, '_fetch_models'),
-  patch.object(App, '_load_fonts'),
-  patch.object(App, '_post_init')
- ):
-  app = App()
-  yield app
-
 @pytest.mark.asyncio
 async def test_mma_stream_event_routing(app_instance: App):
  """Verifies that 'mma_stream' events from AsyncEventQueue reach mma_streams."""