Add PracticeLoop - Practice tool for YouTube videos

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Adds PracticeLoop to the Interact section.

PracticeLoop is a free web tool that helps musicians practice difficult passages by slowing down and looping sections of YouTube videos. It's particularly useful for learning solos, bass lines, piano pieces, and drum patterns from YouTube tutorials and performances.

Key features:

• Speed control (0.25x-2x) without pitch distortion
• A-B loop with keyboard shortcuts
• Progressive speed training (auto-increments speed after N reps)
• Built-in metronome with tap tempo
• Practice timer and streak tracking
• Shareable URLs with pre-configured loops
• PWA support (works offline after first load)

Why it fits:
The Interact section features interactive music learning tools like Ableton's guides and Chrome Music Lab. PracticeLoop complements these by making YouTube a better practice tool for musicians learning by ear.

Live demo: https://musicpracticeapp.netlify.app/
Try it: Paste any YouTube music video URL, set loop points around a solo/passage, slow it down, and practice!

Perfect fit alongside the other interactive learning tools in this section.