Show notifications when a lecture is about to begin

[alexhorn]

No description provided.

[M4GNV5]

Not sure how useful this is without #32. But having native phone notifications probably relies on apple push notifications / firebase cloud messaging (i assume?) and thus only works with a backend which has access to user data? Maybe we can implement this in coorperation with the THI in the future?

For now we could only implement notifications for desktop users which keep the site open using the Notifications API?

[M4GNV5]

https://stackoverflow.com/questions/63819485/sending-push-notifications-to-ios-from-pwa

The Apple-Wallet based way looks interesting, but is iOS only

[M4GNV5]

There are various ways of sending push notifications to mobile devices, but there does not seem to be a privacy-friendly one. All of them require some backend service having access to users timetables.
Privacy is a key concept built into the neuland.app and we should not sacrifice it for a feature that is already available by adding the timetable iCal URL to your iOS/Google/... calendar app.
Instead we could put more effort into #7 and add the possibility to scrape the iCal URL from primuss and show it to the user in our app, without sending the user to the ugly interface to retrieve the URL.