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_spawn_interception.py

@@ -19,7 +19,7 @@ class MockDialog:
   return res
 
 @pytest.fixture
-def mock_ai_client():
+def mock_ai_client() -> None:
  with patch("ai_client.send") as mock_send:
   mock_send.return_value = "Task completed"
   yield mock_send