Migrate from .NET MAUI to Expo + Convex

Complete rewrite of Scry using TypeScript stack:

- Expo/React Native with Expo Router (file-based routing)
- Convex backend (serverless functions + real-time database)
- Adaptive camera system (expo-camera in Expo Go, Vision Camera in production)
- React Native Skia + fast-opencv for image processing
- GDPR-compliant auth setup with Zitadel OIDC (pending configuration)

Key features:
- Card recognition pipeline ported to TypeScript
- Perceptual hashing (192-bit color pHash)
- CLAHE preprocessing for lighting normalization
- Local SQLite cache with Convex sync
- Collection management with offline support

Removes all .NET/MAUI code (src/, test/, tools/).

💘 Generated with Crush

Assisted-by: Claude Opus 4.5 via Crush <crush@charm.land>

components/useColorScheme.web.ts

@@ -0,0 +1,8 @@
+// NOTE: The default React Native styling doesn't support server rendering.
+// Server rendered styles should not change between the first render of the HTML
+// and the first render on the client. Typically, web developers will use CSS media queries
+// to render different styles on the client and server, these aren't directly supported in React Native
+// but can be achieved using a styling library like Nativewind.
+export function useColorScheme() {
+  return 'light';
+}