chore(storybook): align items inside decorator

.storybook/StoryStage.svelte

@@ -9,7 +9,7 @@ let { children, width = 'max-w-3xl' }: Props = $props();
 
 <div class="flex min-h-screen w-full items-center justify-center bg-slate-50 p-8">
     <div class="w-full bg-white shadow-xl ring-1 ring-slate-200 rounded-xl p-12 {width}">
-        <div class="relative">
+        <div class="relative flex justify-center items-center">
             {@render children()}
         </div>
     </div>