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/conftest.py

@@ -14,7 +14,7 @@ from api_hook_client import ApiHookClient
 import ai_client
 
 @pytest.fixture(autouse=True)
-def reset_ai_client():
+def reset_ai_client() -> None:
  """Reset ai_client global state between every test to prevent state pollution."""
  ai_client.reset_session()
  # Default to a safe model
@@ -41,7 +41,7 @@ def kill_process_tree(pid):
   print(f"[Fixture] Error killing process tree {pid}: {e}")
 
 @pytest.fixture(scope="session")
-def live_gui():
+def live_gui() -> None:
  """
     Session-scoped fixture that starts gui_2.py with --enable-test-hooks.
     """