feat(mobile): Add field app with date range navigation

- Add React Native Expo field app for mobile staff
- Use main /appointments/ endpoint with date range support
- Add X-Business-Subdomain header for tenant context
- Support day/week view navigation
- Remove WebSocket console logging from frontend
- Update AppointmentStatus type to include all backend statuses
- Add responsive status legend to scheduler header

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

mobile/field-app/babel.config.js

@@ -0,0 +1,6 @@
+module.exports = function (api) {
+  api.cache(true);
+  return {
+    presets: ['babel-preset-expo'],
+  };
+};