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>

app.json

@@ -0,0 +1,39 @@
+{
+  "expo": {
+    "name": "Scry",
+    "slug": "scry",
+    "version": "1.0.0",
+    "orientation": "portrait",
+    "icon": "./assets/images/icon.png",
+    "scheme": "scry",
+    "userInterfaceStyle": "automatic",
+    "newArchEnabled": true,
+    "splash": {
+      "image": "./assets/images/splash-icon.png",
+      "resizeMode": "contain",
+      "backgroundColor": "#ffffff"
+    },
+    "ios": {
+      "supportsTablet": true
+    },
+    "android": {
+      "adaptiveIcon": {
+        "foregroundImage": "./assets/images/adaptive-icon.png",
+        "backgroundColor": "#ffffff"
+      },
+      "edgeToEdgeEnabled": true,
+      "predictiveBackGestureEnabled": false
+    },
+    "web": {
+      "bundler": "metro",
+      "output": "static",
+      "favicon": "./assets/images/favicon.png"
+    },
+    "plugins": [
+      "expo-router"
+    ],
+    "experiments": {
+      "typedRoutes": true
+    }
+  }
+}