feat: hover micro-interactions on cards, steps and CTA arrow

Disciplinas cards and Mecanismo/ComoEmpezar steps get a subtle lift +
border intensify on hover; the CTA arrow slides right. All gated with
motion-reduce so prefers-reduced-motion users see no movement.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

components/primitives/CTA.tsx

@@ -8,9 +8,10 @@ export function CTA({ href, label, variant = 'light', className = '' }: { href:
   return (
     <a
       href={href}
-      className={`inline-block font-sans font-bold uppercase tracking-wider px-7 py-3.5 text-sm transition-colors ${styles[variant]} ${className}`}
+      className={`group inline-block font-sans font-bold uppercase tracking-wider px-7 py-3.5 text-sm transition-colors ${styles[variant]} ${className}`}
     >
-      {label} <span aria-hidden="true">→</span>
+      {label}{' '}
+      <span aria-hidden="true" className="inline-block transition-transform duration-300 ease-out group-hover:translate-x-1 motion-reduce:transform-none motion-reduce:transition-none">→</span>
     </a>
   );
 }