The root .env is shared by both apps. app/web and app/mobile each keep their own .env for environment-specific variables.
Your code + Metro — the live JS server, hot reload.
Preview before you ship — fastest option first.
The one thing: native → build · everything else → update.
Build path only: Expo packages & signs, Apple distributes.
Arrives on a real device. The loop closes.
The flow, top to bottom · Claude Code writes 100% of it