how can I set the app icon badge

To set the app icon badge, you can use the UNUserNotificationCenter to manage notifications and update the badge count. Here's a basic example of how you can achieve this:

Request Notification Permissions: First, you need to request permission to display notifications.

import UserNotifications

UNUserNotificationCenter.current().requestAuthorization(options: [.badge, .sound, .alert]) { (granted, error) in
    if granted {
        print("Permission granted")
    } else if let error = error {
        print("Error: \(error.localizedDescription)")
    }
}

Update the Badge Count: You can update the badge count by setting the badge property of a UNMutableNotificationContent object.

let content = UNMutableNotificationContent()
content.badge = NSNumber(value: 1) // Set the badge number

let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 1, repeats: false)
let request = UNNotificationRequest(identifier: "badgeNotification", content: content, trigger: trigger)

UNUserNotificationCenter.current().add(request) { (error) in
    if let error = error {
        print("Error: \(error.localizedDescription)")
    }
}

Clear the Badge Count: To clear the badge count, you can set it to 0.
```
UIApplication.shared.applicationIconBadgeNumber = 0
```

For more detailed information on how to extend your app's controls across the system, you can refer to the session Extend your app’s controls across the system (12:25).

If you need more information on how to integrate these features into your app, you might find the session Bring your app’s core features to users with App Intents (08:06) helpful.