refactor: move solo/mute to header as icon buttons and fix waveform height

Changes:
- Solo and Mute buttons now appear as icon buttons in the track header (next to trash)
- Removed redundant solo/mute button row from the expanded controls
- Cleaner, more compact layout
- Canvas now uses parent container's size for proper full-height rendering
- Added track.height to canvas effect dependencies

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

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

components/tracks/Track.tsx

@@ -84,8 +84,12 @@ export function Track({
     const ctx = canvas.getContext('2d');
     if (!ctx) return;
 
+    // Use parent container's size since canvas is absolute positioned
+    const parent = canvas.parentElement;
+    if (!parent) return;
+
     const dpr = window.devicePixelRatio || 1;
-    const rect = canvas.getBoundingClientRect();
+    const rect = parent.getBoundingClientRect();
 
     canvas.width = rect.width * dpr;
     canvas.height = rect.height * dpr;
@@ -147,7 +151,7 @@ export function Track({
       ctx.lineTo(playheadX, height);
       ctx.stroke();
     }
-  }, [track.audioBuffer, track.color, track.collapsed, zoom, currentTime, duration]);
+  }, [track.audioBuffer, track.color, track.collapsed, track.height, zoom, currentTime, duration]);
 
   const handleCanvasClick = (e: React.MouseEvent<HTMLCanvasElement>) => {
     if (!onSeek || !duration) return;
@@ -216,6 +220,33 @@ export function Track({
             )}
           </div>
 
+          {/* Solo Button */}
+          <Button
+            variant="ghost"
+            size="icon-sm"
+            onClick={onToggleSolo}
+            title="Solo track"
+            className={cn(track.solo && 'bg-yellow-500/20 hover:bg-yellow-500/30')}
+          >
+            <Headphones className={cn('h-4 w-4', track.solo && 'text-yellow-500')} />
+          </Button>
+
+          {/* Mute Button */}
+          <Button
+            variant="ghost"
+            size="icon-sm"
+            onClick={onToggleMute}
+            title="Mute track"
+            className={cn(track.mute && 'bg-red-500/20 hover:bg-red-500/30')}
+          >
+            {track.mute ? (
+              <VolumeX className="h-4 w-4 text-red-500" />
+            ) : (
+              <Volume2 className="h-4 w-4" />
+            )}
+          </Button>
+
+          {/* Remove Button */}
           <Button
             variant="ghost"
             size="icon-sm"
@@ -270,38 +301,6 @@ export function Track({
                 step={0.01}
               />
             </div>
-
-            {/* Solo / Mute Buttons */}
-            <div className="flex gap-2">
-              <Button
-                variant={track.solo ? 'default' : 'outline'}
-                size="sm"
-                onClick={onToggleSolo}
-                className={cn(
-                  'flex-1 text-xs',
-                  track.solo && 'bg-yellow-500/20 hover:bg-yellow-500/30 text-yellow-500'
-                )}
-              >
-                <Headphones className="h-3.5 w-3.5 mr-1.5" />
-                Solo
-              </Button>
-              <Button
-                variant={track.mute ? 'default' : 'outline'}
-                size="sm"
-                onClick={onToggleMute}
-                className={cn(
-                  'flex-1 text-xs',
-                  track.mute && 'bg-red-500/20 hover:bg-red-500/30 text-red-500'
-                )}
-              >
-                {track.mute ? (
-                  <VolumeX className="h-3.5 w-3.5 mr-1.5" />
-                ) : (
-                  <Volume2 className="h-3.5 w-3.5 mr-1.5" />
-                )}
-                Mute
-              </Button>
-            </div>
           </>
         )}
       </div>