feat: replace clsx with cn util

src/widgets/ComparisonView/ui/Sidebar/Sidebar.svelte

@@ -5,12 +5,12 @@
     Content (font list, controls) is injected via snippets.
 -->
 <script lang="ts">
+import { cn } from '$shared/lib';
 import {
     ButtonGroup,
     Label,
     ToggleButton,
 } from '$shared/ui';
-import clsx from 'clsx';
 import type { Snippet } from 'svelte';
 import {
     type Side,
@@ -40,7 +40,7 @@ let {
 </script>
 
 <div
-    class={clsx(
+    class={cn(
         'flex flex-col h-full',
         'w-80',
         'bg-surface dark:bg-dark-bg',