aparande/workout-tracker ? reverse-engineered prompt

Build me an Apple Watch workout app that can automatically count exercise repetitions.

I want the watch app to let the user either calibrate for a specific exercise or start counting right away. In calibration, it should guide them through 5 reps and vibrate when it is time to change position, so they can learn the movement pattern. In count mode, the user starts a workout and the watch keeps track of reps in real time while they move.

Also make an iPhone companion app that can receive the workout sensor data as JSON so I can inspect it and debug the motion tracking. The watch should upload the sensor data from each session, whether it was calibration or counting.

Keep it simple and usable, with a clean watch home screen and a clear counting screen. If you need to check current Apple Watch or iOS docs while building, go ahead and look them up online.