feat(ComparisonView): add color transition for each character

src/widgets/ComparisonView/ui/Character/Character.svelte

@@ -52,6 +52,7 @@ $effect(() => {
             <span
                 class={cn(
                     'char-inner',
+                    'transition-colors duration-300',
                     isPast
                         ? 'text-swiss-black/75 dark:text-brand/75'
                         : 'text-neutral-950 dark:text-white',