skulptapp/skulpt ? reverse-engineered prompt

Build me a workout tracker app for iPhone and Android that works fully offline first, with all the data stored on the device, and optional sync if I turn it on later.

I want it to let me plan workouts, log sets live while I’m training, and look back at my workout history, exercise volume, and personal records. It should handle the usual set types like warm up, working, drop, failure, time, and distance, plus supersets, trisets, and circuits. Add body measurements with charts, configurable rest timers with sound and haptics, light and dark mode, and support for kg or lb, km or mi, cm or in, and Celsius or Fahrenheit.

If it makes sense, include Apple Watch control, Live Activities on iPhone, and import from Apple Health and Google Health Connect. Keep it free and subscription free, and look up current docs online if you need to fill in any missing platform details.