feat(visualizer): add multiple visualizers with mouse tracking and beat response

- Add BaseVisualizer class for shared visualizer logic
- Add Helix visualizer (DNA helix with rungs, beat compression/bounce)
- Add Tunnel visualizer (ring tunnel with depth parallax)
- Refactor SphereVisualizer to extend BaseVisualizer
- Add mouse tracking to all visualizers (canvas-relative, centered)
- Add visualizer switching via logo click (persisted to localStorage)
- Add beat-responsive bouncing and compression effects

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

config/_default/params.toml

@@ -1,4 +1,4 @@
-description = "Valknar's audio"
+description = "Valknar's Pivoine.Art"
 author = "Valknar"
 email = "valknar@pivoine.art"