Fix: Use _stop instead of _stop_event to match reference

app.py

@@ -241,18 +241,18 @@ class FrameScheduler(threading.Thread):
         self.n_steps = int(n_steps)
         self.cfg = float(cfg)
         self.clamp = bool(clamp)
-        self._stop_event = threading.Event()
+        self._stop = threading.Event()
         # FPS tracking
         self.frame_times = []
         self.last_frame_time = None
 
     def stop(self):
-        self._stop_event.set()
+        self._stop.set()
 
     def run(self):
         global frame_index, latest_action
         next_tick = time.perf_counter()
-        while not self._stop_event.is_set():
+        while not self._stop.is_set():
             start = time.perf_counter()
             if start - next_tick > self.frame_period * 0.75:
                 next_tick = start + self.frame_period