How to update Live Activities from a server

1. Define ActivityAttributes and a ContentState that your Lock Screen UI can render.
2. Start the activity on device with LiveHive.start() (or Activity.request + LiveHive.register).
3. For first success, open the activity in the Live Hive dashboard and tap Send test update. No backend required.
4. When your domain state changes, your backend POSTs a Live Hive update whose content_state matches that struct.
5. When the job is done, send an end event.

With Live Hive, token registration is register and HTTP updates are update and end. You still add a Widget Extension. Machine-readable: /llms.txt, /openapi.json.