fix: remove border-t from effects bar to eliminate gap with automation bar

- Removed border-t from effects bar container
- Keeps border-b for bottom edge separation
- No gap between automation and effects bars in both folded and unfolded states

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

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

components/tracks/TrackList.tsx

@@ -295,7 +295,7 @@ export function TrackList({
 
                   {/* Effects Bar - Always visible at bottom */}
                   {!track.collapsed && (
-                    <div className="absolute bottom-0 left-0 right-0 z-10 pointer-events-auto bg-card/90 backdrop-blur-sm border-t border-b border-border">
+                    <div className="absolute bottom-0 left-0 right-0 z-10 pointer-events-auto bg-card/90 backdrop-blur-sm border-b border-border">
                       {/* Effects Header - Collapsible */}
                       <div
                         className="flex items-center gap-2 px-3 py-1.5 cursor-pointer hover:bg-accent/30 transition-colors"