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_token_usage.py

@@ -7,7 +7,7 @@ sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
 
 import ai_client
 
-def test_token_usage_tracking():
+def test_token_usage_tracking() -> None:
  ai_client.reset_session()
  # Mock an API response with token usage
  usage = {"prompt_tokens": 100, "candidates_tokens": 50, "total_tokens": 150}