fix: match automation controls width to track controls (w-48 = 192px)

Fixed playhead marker alignment issue:
- Changed automation controls from w-[180px] to w-48 (192px)
- Now matches track controls panel width exactly
- Playhead marker now aligns perfectly between waveform and automation

Technical details:
- Track controls use Tailwind's w-48 class (12rem = 192px)
- Automation controls were using w-[180px] causing 12px misalignment
- Both sidebars now use consistent w-48 sizing

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

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

components/tracks/Track.tsx

@@ -775,8 +775,8 @@ export function Track({
 
         return selectedLane ? (
           <div className="flex border-b border-border">
-            {/* Left: Automation Controls (matching track controls width) */}
-            <div className="w-[180px] flex-shrink-0 bg-muted/30 border-r border-border/50 p-2 flex flex-col gap-2">
+            {/* Left: Automation Controls (matching track controls width - w-48 = 192px) */}
+            <div className="w-48 flex-shrink-0 bg-muted/30 border-r border-border/50 p-2 flex flex-col gap-2">
               {/* Parameter selector dropdown */}
               <select
                 value={selectedParameterId}