Expo Dev Client

This handles the whole workflow for creating custom Expo development clients when you need to test native code that won't run in regular Expo Go. It sets up your eas.json with the right development profile, builds iOS clients that automatically submit to TestFlight, and handles local Android builds with proper ADB installation commands. The skill is smart about when you actually need a dev client versus just using Expo Go. Most useful when you're adding native modules or Apple-specific features like widgets and need to test on real devices before production builds.