Adapt to librespot core changes

[dcordonu]

librespot now uses SpotifyUri instead of SpotifyId. This allows to easily keep track of the type of resource (track, episode, album, playlist, etc)

[maugelves]

Tested this branch and it fixes the Track is unavailable error that affects every track on current master (which is still pinned to librespot 0.6.0, broken since Spotify sunset their V2 Ads API on 2025-08-05).

Environment

• macOS 15.6.1 (Apple Silicon / arm64)
• Rust 1.96.0
• Built with: cargo install --git https://github.com/dcordonu/spotify-dl.git --branch feature/adapt-to-librespot-core-changes (commit 773e517)
• Resolves librespot 0.8.0

Result

• Downloaded a full 38-track playlist with a Premium account: 0 Track is unavailable errors, all FLACs written correctly. MP3 output (-f mp3) also works.
• On master (librespot 0.6.0) the exact same playlist/account returned Track is unavailable for 100% of tracks.

Works correctly here — would be great to get this merged. Thanks for the fix! 🙏