feat: add notification events handling and MQTT integration

- Implemented notification event publishing with a new NotificationEventPublisher interface.
- Created a noopNotificationEventPublisher for testing purposes.
- Added functionality to publish notification created events via MQTT.
- Introduced a new stream event publisher for handling job logs and updates.
- Added database migration for popup_ads table.
- Created tests for notification events and popup ads functionality.
- Established MQTT connection and publishing helpers for event messages.

internal/service/payment_helpers.go

@@ -118,6 +118,9 @@ func (s *appServices) executePaymentFlow(ctx context.Context, input paymentExecu
 	}
 	result.Subscription = subscription
 	result.WalletBalance = walletBalance
+	if notification := latestNotificationForPayment(result.Payment, subscription, input.Plan, invoiceID); notification != nil {
+		s.publishNotificationCreated(ctx, notification)
+	}
 	return result, nil
 }