fix(music): spotify playlists, auto-leave, stats logging

- Fix Spotify playlist loading (401 error) by enabling preferPartnerApi
  in lavasrc (uses Partner API instead of v1 /items endpoint)
- Remove noisy DEBUG stats logging (change to TRACE)
- Increase auto-leave timer from 2 to 3 minutes
- Add proper voice disconnect on auto-leave via JDA AudioManager
- Increase playlist/album load limit from 6 to 10 (1000 tracks)

lavalink/application.yml

@@ -22,8 +22,9 @@ plugins:
       clientId: "${SPOTIFY_CLIENT_ID}"
       clientSecret: "${SPOTIFY_CLIENT_SECRET}"
       countryCode: "RU"
-      playlistLoadLimit: 6
-      albumLoadLimit: 6
+      playlistLoadLimit: 10
+      albumLoadLimit: 10
+      preferPartnerApi: true
     applemusic:
       countryCode: "RU"
       mediaType: "music"