jtrejo13/fitness-learning ? reverse-engineered prompt

Build me a lightweight Apple Watch app that can tell what workout I am doing in real time and show the result on the watch while I exercise.

I want it to use motion data from the watch, train on a few common workouts like elliptical, rowing, pushups, and treadmill, and then automatically recognize the activity instead of making the user pick it manually. Please include the data parsing and analysis pieces too, so I can take raw workout exports, turn them into usable training data, and retrain the model if needed. If it helps, use the existing notebook style for exploration and keep the training pipeline simple and understandable.

The app should have a basic start and stop flow, and a clear screen that shows what workout it thinks I am doing. If you need to look up current Apple Watch or Core Motion docs online, go ahead.