feat: implement TimeScale component with proper zoom calculation

- Add TimeScale component with canvas-based rendering
- Use 5 pixels per second base scale (duration * zoom * 5)
- Implement viewport-based rendering for performance
- Add scroll synchronization with waveforms
- Add 240px padding for alignment with track controls and master area
- Apply custom scrollbar styling
- Update all waveform width calculations to match timeline

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

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

components/tracks/Track.tsx

@@ -773,8 +773,8 @@ export function Track({
           className="relative h-full"
           style={{
             minWidth:
-              track.audioBuffer && zoom > 1
-                ? `${duration * zoom * 100}px`
+              track.audioBuffer && zoom >= 1
+                ? `${duration * zoom * 5}px`
                 : "100%",
           }}
         >