Add custom hidden scrollbar styles and clean up code

Introduced CSS classes to hide scrollbars while maintaining scrollability across browsers. Also removed unnecessary blank lines in frameRenderer.ts for code cleanliness.

src/index.css

@@ -77,6 +77,16 @@
     transition: left 33ms linear, right 33ms linear;
   }
   
+  /* Hidden scrollbar - still scrollable but invisible */
+  .custom-scrollbar {
+    scrollbar-width: none; /* Firefox */
+    -ms-overflow-style: none; /* IE/Edge */
+  }
+  
+  .custom-scrollbar::-webkit-scrollbar {
+    display: none; /* Chrome, Safari, Opera */
+  }
+  
   /* Smooth playback scrubber */
   input[type="range"] {
     -webkit-appearance: none;

src/lib/exporter/frameRenderer.ts

@@ -311,8 +311,6 @@ export class FrameRenderer {
       const scaleY = this.config.height / previewHeight;
       const scaleFactor = (scaleX + scaleY) / 2;
 
-
-
       await renderAnnotations(
         this.compositeCtx,
         this.config.annotationRegions,