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>

performance_monitor.py

@@ -3,7 +3,7 @@ import psutil
 import threading
 
 class PerformanceMonitor:
- def __init__(self):
+ def __init__(self) -> None:
   self._start_time = None
   self._last_frame_time = 0.0
   self._fps = 0.0
@@ -32,7 +32,7 @@ class PerformanceMonitor:
   self._cpu_thread = threading.Thread(target=self._monitor_cpu, daemon=True)
   self._cpu_thread.start()
 
- def _monitor_cpu(self):
+ def _monitor_cpu(self) -> None:
   while not self._stop_event.is_set():
   # psutil.cpu_percent with interval=1.0 is blocking for 1 second.
   # To be responsive to stop_event, we use a smaller interval or no interval 
@@ -49,21 +49,21 @@ class PerformanceMonitor:
      break
     time.sleep(0.1)
 
- def start_frame(self):
+ def start_frame(self) -> None:
   self._start_time = time.time()
 
- def record_input_event(self):
+ def record_input_event(self) -> None:
   self._last_input_time = time.time()
 
- def start_component(self, name: str):
+ def start_component(self, name: str) -> None:
   self._comp_start[name] = time.time()
 
- def end_component(self, name: str):
+ def end_component(self, name: str) -> None:
   if name in self._comp_start:
    elapsed = (time.time() - self._comp_start[name]) * 1000.0
    self._component_timings[name] = elapsed
 
- def end_frame(self):
+ def end_frame(self) -> None:
   if self._start_time is None:
    return
   end_time = time.time()
@@ -80,7 +80,7 @@ class PerformanceMonitor:
    self._frame_count = 0
    self._fps_last_time = end_time
 
- def _check_alerts(self):
+ def _check_alerts(self) -> None:
   if not self.alert_callback:
    return
   now = time.time()
@@ -114,6 +114,6 @@ class PerformanceMonitor:
    metrics[f'time_{name}_ms'] = elapsed
   return metrics
 
- def stop(self):
+ def stop(self) -> None:
   self._stop_event.set()
   self._cpu_thread.join(timeout=2.0)