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_live_gui_integration.py

@@ -7,7 +7,7 @@ from events import UserRequestEvent
 import ai_client
 
 @pytest.fixture
-def mock_app():
+def mock_app() -> None:
  with (
   patch('gui_2.load_config', return_value={
     "ai": {"provider": "gemini", "model": "model-1", "temperature": 0.0, "max_tokens": 100, "history_trunc_limit": 1000},