Added 10-Band EQ with presets.

More sites “just work” now: Volume boost, EQ, and presets are more reliable on sites like Bandcamp and SoundCloud.

Better behavior: Uses a “Basic Mode” when advanced boosting/EQ isn’t possible (so playback stays stable). You’ll see a clear notice when this happens.

General fixes: Smoother switching between sites and fewer cases where controls appear to do nothing.