Personalized OneSignal Notifications Fix

Our Laravel-based chatbot platform pulls WhatsApp Business messages and shows them in a Flutter mobile app. OneSignal is already wired up, yet every incoming WhatsApp message triggers a push to every account, and the Flutter side still doesn’t display those pushes at all.

Here’s what I need:

• Re-configure OneSignal on the Laravel backend so only the intended recipient gets a push whenever a new message arrives. The event type is strictly “Message received.”
• The payload should carry a short summary, not the full content.
• Notifications must be delivered automatically; users don’t need a mute or toggle option.
• Update the Flutter app so it registers correctly with OneSignal (iOS and Android), handles the notification in foreground/background states, and routes the user to the relevant chat when tapped.

I’ll provide full access to the current Laravel codebase, OneSignal keys, and the Flutter project. Once you’re done I expect to see device-specific pushes working in real time and reflected in the Flutter UI without broadcasting to other accounts.