The notification server needs to send a notifications list to the client, to make sure the user sees all of their notifications.

This is relevant because the client may not have all the same data available as the notification server has. The notification server is expected to see "everything" because it sends out the emails, etc.

But, the notification list is ever-increasing. So the server should either support pagination (and the client will fetch things it already has - only stopping when the user stops scrolling down), or we should develop some range-based-set-reconciliation.

For content that is p2p synced, the client can still generate its own notifications, without connection to the notif server. So we will need a consistent mechanism to generate a notification ID.