Refactor mobile to fix dependency resolution and add polyfills

Update Expo and React dependencies to compatible versions. Create a
custom Metro config to resolve module conflicts in the workspace and
map Jest modules to local node_modules.

Add a SharedArrayBuffer polyfill for older runtimes and introduce an
adapter for expo-notifications to abstract direct imports.

apps/mobile/index.ts

@@ -1,3 +1,4 @@
+import './src/polyfills/sharedArrayBuffer';
 import { registerRootComponent } from 'expo';
 
 import App from './App';