Add motion detection before object detection

src/config.hpp

@@ -51,6 +51,8 @@ struct AppConfig {
     bool export_csv = true;
     std::string cross_csv;
 
+    bool motion_detection_enabled = false;
+    float motion_threshold = 5.0f;
     int warmup_frames = 30;
     int reconnect_delay_sec = 3;
     int max_reconnect_attempts = 0;