ischys-app/Ischys ? reverse-engineered prompt

Build me a private workout tracker app that runs entirely on the phone, with no account, no cloud, and no backend.

I want it to let people log workouts, set by set, with weight and reps, track rest timers, build routines, and prefill the next session from the last one so progression is easy. It should also show useful stats like personal records, estimated 1RM, volume, streaks, workout history, and simple charts for each exercise. Add export and import so users can back up their data or move in from another app.

It should feel super clean and easy to use mid workout, with a dark, high contrast design. If you can, include iPhone and Android support, plus watch support and health integrations where the platform allows. Look up current docs online if you need to, and make sure everything stays local and privacy focused.