Shashwat-CODING/Muzo ? reverse-engineered prompt

Build me a polished Flutter app called Muzo that feels like a premium YouTube Music client, but privacy focused and ad free. I want it to let people search, play, and manage music easily, with background playback, offline downloads, playlists, favorites, history, and a smart cache so songs start fast. The app should have synced lyrics with a karaoke style view, a sleep timer, and support for importing Spotify playlists. Make the design modern and stylish with a glassy look, dark and light themes, smooth animations, and a responsive layout that still looks good on phone, tablet, and desktop.

It should work without requiring an account, but also allow sign in for optional cloud sync and uploads. Add deep links so shared links can open songs, artists, albums, and playlists directly in the app. If you need to check current Flutter or package docs while building, go ahead and look them up online.