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>

.justfile

@@ -3,45 +3,17 @@
 set shell := ["C:/Program Files/Git/usr/bin/bash.exe", "-c"]
 set unstable := true
 
+mod emu '.just/emu.just'
+
 # Android SDK paths
 
 android_sdk := replace(env('LOCALAPPDATA'), '\', '/') / "Android/Sdk"
 adb := android_sdk / "platform-tools/adb.exe"
-emulator := android_sdk / "emulator/emulator.exe"
-camera_virtual := "-camera-back virtualscene -virtualscene-poster wall=\"" + (justfile_directory() / "TestImages/reference_alpha/serra_angel.jpg") + "\""
-camera_webcam := "-camera-back webcam0 -camera-front webcam0"
 
 [private]
 @default:
     just --list
 
-# Start emulator in background
-emu camera="virtual":
-    {{ emulator }} -avd Pixel_6 {{ if camera == "virtual" { camera_virtual } else { camera_webcam } }} -no-snapshot-load -gpu host
-
-# Kill the running emulator
-emu-kill:
-    {{ adb }} emu kill
-
-# Wait for emulator to fully boot (timeout after 2 minutes)
-[script]
-emu-wait:
-    # Wait for Android emulator to boot with timeout
-    TIMEOUT=120
-
-    echo "Waiting for emulator to boot..."
-
-    for ((i=TIMEOUT; i>0; i--)); do
-        if [ "$({{ adb }} shell getprop sys.boot_completed 2>/dev/null)" = "1" ]; then
-            echo "Emulator ready"
-            exit 0
-        fi
-        sleep 1
-    done
-
-    echo "Emulator failed to boot within 2 minutes"
-    exit 1
-
 # Build a project
 build project="src/Scry.App" target="net10.0-android":
     @echo "Building {{ project }}..."
@@ -79,6 +51,30 @@ gen-db: (build "tools/DbGenerator" "net10.0")
     dotnet run --project tools/DbGenerator --no-build -- src/Scry.App/Resources/Raw/card_hashes.db
     @echo "Completed generating the database"
 
-# Full workflow: start emulator, wait, run with hot reload
+# Start Expo dev server with Convex (hot reload)
 dev:
-    dotnet watch --project src/Scry.App -f net10.0-android
+    bun run dev
+
+# Start just the Expo dev server
+start:
+    bun run dev:expo
+
+# Start just Convex dev server
+convex-dev:
+    bun run dev:convex
+
+# Run Expo app on Android emulator
+android:
+    bun run android
+
+# Install Expo app dependencies
+expo-install:
+    bun install
+
+# Run hash migration to Convex
+expo-migrate:
+    bun run migrate
+
+# TypeScript check for Expo app
+expo-typecheck:
+    bun run typecheck