StanfordBDHG/HealthGPT ? reverse-engineered prompt

Build me an iPhone app that lets people ask questions about their Apple Health data in plain English and get easy to understand answers back in a chat style interface.

I want it to feel like a friendly health assistant, with support for voice input and spoken responses, and a way to export the conversation. It should connect to Apple Health, pull common data like sleep, steps, active energy, exercise minutes, heart rate, and body mass, then use that data to answer questions like how well I slept last week or whether my activity has improved.

Please include a settings screen where I can choose how the AI runs, either through a cloud model or a local private option, and make sure the app clearly explains that health data privacy matters. If you need current docs for the Apple or AI parts, look them up online before you wire it up.