Enable native receipt tracking and Expo App Groups in 0.5.0

[philippeauriach]

React Native SDK 0.5.0 adds automatic notification receipt tracking on iOS and Android, without requiring a JavaScript event subscription.

• Reports receipts independently of onOpened, including foreground notifications whose presentation is suppressed.
• Recovers notifications still present in Notification Center or the notification tray when the app starts or resumes. Opening the app directly does not count as opening a notification.
• Keeps pending events and their timestamps on the device and retries when connectivity returns.
• Adds an optional Expo appGroup setting to capture receipts in the iOS notification service extension and report them when the app next runs.

The README covers setup, platform limits and native rebuild requirements. Receipt confirmation is separate from display and reading.