fix: adjust volume slider max to 100% (was 200%)

Changed volume slider max from 2 to 1 (0-100% range).
Default volume remains at 0.8 (80%).

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

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

components/layout/SidePanel.tsx

@@ -226,7 +226,7 @@ export function SidePanel({
                               value={track.volume}
                               onChange={(value) => onUpdateTrack(track.id, { volume: value })}
                               min={0}
-                              max={2}
+                              max={1}
                               step={0.01}
                             />
                           </div>