feat(ComparisonSlider): add appearance animation to the slider line

src/widgets/ComparisonSlider/ui/ComparisonSlider/components/SliderLine.svelte

@@ -4,6 +4,8 @@
 -->
 <script lang="ts">
 import { cn } from '$shared/shadcn/utils/shadcn-utils';
+import { cubicOut } from 'svelte/easing';
+import { fade } from 'svelte/transition';
 
 interface Props {
     /**
@@ -27,6 +29,7 @@ let { sliderPos, isDragging }: Props = $props();
     )}
     style:left="{sliderPos}%"
     style:will-change={isDragging ? 'left' : 'auto'}
+    in:fade={{ duration: 300, delay: 150, easing: cubicOut }}
 >
     <!-- We use part of lucide cursor svg icon as a handle -->
     <svg