edzdgx/auto-turret ? reverse-engineered prompt

Build me a simple Raspberry Pi project that turns a paintball turret toward a detected face and can fire the trigger servo when a target is found.

I want a Python script that uses the Pi camera to read frames, OpenCV to detect faces, and GPIO PWM to control three servos for left and right, up and down, and the trigger. It should keep tracking the face in the center of the camera view by adjusting the servos smoothly, and I want it to be easy to calibrate for my hardware setup.

Please include clear setup instructions for a Raspberry Pi 3, the camera module, and the servo wiring, plus any install steps I need for OpenCV and camera support. If anything depends on current library behavior, look up the latest docs online if needed. Also make sure the code is organized and easy to run from one main file.