Predidit/Kazumi ? reverse-engineered prompt

I'd like to build a cross-platform anime streaming app using Flutter so it can run on desktop (Windows, macOS, Linux) and mobile (Android, iOS). The app shouldn't host any content itself. Instead, its core feature should be letting users create and share simple rules to pull in anime from various online sources.

The app needs a nice UI with a catalog of shows, a search function, a timetable for currently airing anime, and a personal watchlist. The video player is super important: it needs to support danmaku (the bullet comments that fly across the screen), playback speed controls, and remember my watch history. I also want a cool feature that can do real-time video upscaling to make lower-res shows look sharper. It would be awesome to also include a "watch together" feature to sync playback with friends, and could you make sure my watch history and lists sync across all my devices?