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_gui_async_events.py

@@ -50,7 +50,7 @@ def test_handle_generate_send_pushes_event(mock_gui):
   assert event.disc_text == "disc_text"
   assert event.base_dir == "."
 
-def test_user_request_event_payload():
+def test_user_request_event_payload() -> None:
  payload = UserRequestEvent(
   prompt="hello",
   stable_md="md",
@@ -66,7 +66,7 @@ def test_user_request_event_payload():
  assert d["base_dir"] == "."
 
 @pytest.mark.asyncio
-async def test_async_event_queue():
+async def test_async_event_queue() -> None:
  from events import AsyncEventQueue
  q = AsyncEventQueue()
  await q.put("test_event", {"data": 123})