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_async_events.py

@@ -2,7 +2,7 @@ import asyncio
 import pytest
 from events import AsyncEventQueue
 
-def test_async_event_queue_put_get():
+def test_async_event_queue_put_get() -> None:
  """Verify that an event can be asynchronously put and retrieved from the queue."""
 
  async def run_test():
@@ -15,7 +15,7 @@ def test_async_event_queue_put_get():
   assert ret_payload == payload
  asyncio.run(run_test())
 
-def test_async_event_queue_multiple():
+def test_async_event_queue_multiple() -> None:
  """Verify that multiple events can be asynchronously put and retrieved in order."""
 
  async def run_test():
@@ -30,7 +30,7 @@ def test_async_event_queue_multiple():
   assert val2 == 2
  asyncio.run(run_test())
 
-def test_async_event_queue_none_payload():
+def test_async_event_queue_none_payload() -> None:
  """Verify that an event with None payload works correctly."""
 
  async def run_test():