App Store card → article zoom (expo-router)

Three parts that only work as a set: a poster card, the zoom transition, and the article screen it lands on. Working reference implementation: mobile-app/src/components/chat/discover.tsx (card) and mobile-app/src/app/(tabs)/chat/discover/[slug].tsx (destination), with the tint library in mobile-app/src/lib/image-tint.ts.

Requirements

• expo-router above v55 (this repo runs ~57.0.4, SDK 57) — Link.AppleZoom / Link.AppleZoomTarget don't exist in older routers.
• expo-image — supplies the blurhash placeholder AND Image.generateBlurhashAsync for the tint.
• iOS 18+ for the zoom itself. Off iOS (and on older iOS) the components are a passthrough: the press degrades to a plain stack push. Ship it anyway — nothing crashes, Android just pushes.

The transition — rules that are load-bearing