nextcloud/news — reverse-engineered prompt

Build me a Nextcloud app called News that works as an RSS and Atom feed reader inside Nextcloud. I want users to add feed URLs, refresh them, browse the latest items, open an item to read it, and see which feeds have new posts.

Please make it feel like a normal Nextcloud app, not a separate website. It should fetch and parse common RSS and Atom feeds reliably, store the feed items for each user, and handle bad or broken feed URLs in a friendly way.

Also include a simple REST API so other apps or clients can read and manage the same feeds. Add basic documentation for setup, troubleshooting, and integration. Use the current Nextcloud app docs online if you need to check anything.