Prepare for production build

- Downgrade react-native to 0.81.5 (matches Expo SDK 54)
- Downgrade react to 19.1.0 and related @react-native packages
- Disable New Architecture (react-native-nfc-manager untested)
- Add expo install/doctor exclusions for version-locked deps
- Configure babel to strip console.log/warn in production
- Add logger utility for development-only logging
- Add component and data module exports

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app.json

@@ -6,7 +6,7 @@
     "orientation": "portrait",
     "icon": "./assets/icon.png",
     "userInterfaceStyle": "dark",
-    "newArchEnabled": true,
+    "newArchEnabled": false,
     "splash": {
       "backgroundColor": "#000000"
     },