refactor(types): auto -> None sweep across entire codebase

Applied 236 return type annotations to functions with no return values
across 100+ files (core modules, tests, scripts, simulations).
Added Phase 4 to python_style_refactor track for remaining 597 items
(untyped params, vars, and functions with return values).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_gui2_layout.py

@@ -3,7 +3,7 @@ from unittest.mock import patch
 from gui_2 import App
 
 @pytest.fixture
-def app_instance():
+def app_instance() -> None:
  with (
   patch('gui_2.load_config', return_value={'gui': {'show_windows': {}}}),
   patch('gui_2.save_config'),