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/visual_diag.py

@@ -9,7 +9,7 @@ if PROJECT_ROOT not in sys.path:
 
 from api_hook_client import ApiHookClient
 
-def diag_run():
+def diag_run() -> None:
  print("Launching GUI for manual inspection + automated hooks...")
  # Use a log file for GUI output
  with open("gui_diag.log", "w") as log_file: