feat(disciplinas): la tarjeta y su hebra pasan a ser la misma cosa

El dibujo de convergencia llevaba desde el principio al lado de las tres
tarjetas sin relación con ellas: tres objetos sueltos en una página. Al
señalar una disciplina, su hebra se enciende en dorado y engorda, y las
otras dos se apagan al 35%.

Es mejora solo con puntero, y a propósito: no esconde nada. Las tres
tarjetas y las tres hebras están completas sin tocar el ratón, así que
quien no lo tenga no pierde nada.

Verificado en navegador, no solo en jsdom: al señalar «Digital» la hebra
central queda en rgb(196,148,46) —el dorado de marca— a 3,5px, y las
otras en rgba(170,170,170,0.35) a 2px.

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

components/sections/Disciplinas.tsx

@@ -1,4 +1,5 @@
 'use client';
+import { useState } from 'react';
 import { motion } from 'framer-motion';
 import { Container } from '@/components/primitives/Container';
 import { TarjetaSpotlight } from '@/components/primitives/TarjetaSpotlight';
@@ -11,6 +12,11 @@ const ICONOS: IconoNombre[] = ['comunicacion', 'digital', 'experiencias'];
 
 export function Disciplinas() {
   const reduced = usePrefersReducedMotion();
+  // Which discipline the reader is pointing at, so its strand lights up in the
+  // drawing above. A pointer-only enhancement on purpose: it reveals nothing —
+  // all three cards and all three strands are fully there without it — so
+  // nobody loses anything by not having a mouse.
+  const [senalada, setSenalada] = useState<number | null>(null);
   return (
     <section className="bg-white">
       <Container className="py-16 md:py-24">
@@ -21,12 +27,14 @@ export function Disciplinas() {
         <motion.div variants={fadeInUp} initial="hidden" whileInView="visible" viewport={viewportOnce} {...motionProps(reduced)}
           className="mt-4 md:flex md:items-center md:justify-between md:gap-10">
           <p className="text-gris-medio text-lg">{disciplinas.lead}</p>
-          <IlustracionConvergencia className="mt-6 md:mt-0 w-56 md:w-64 h-auto shrink-0" />
+          <IlustracionConvergencia className="mt-6 md:mt-0 w-56 md:w-64 h-auto shrink-0" activa={senalada} />
         </motion.div>
         <motion.ul variants={staggerContainer} initial="hidden" whileInView="visible" viewport={viewportOnce} {...motionProps(reduced)}
           className="mt-12 grid gap-6 md:grid-cols-3 list-none p-0">
           {disciplinas.items.map((item, i) => (
             <motion.li key={item.name} variants={fadeInUp}
+              onPointerEnter={() => setSenalada(i)}
+              onPointerLeave={() => setSenalada(null)}
               className="transition-transform duration-300 ease-out hover:-translate-y-1.5 motion-reduce:transform-none motion-reduce:transition-none">
               <TarjetaSpotlight className="h-full rounded-lg bg-azul-profundo text-white p-7">
                 <div className="grid place-items-center w-14 h-14 rounded-full bg-white/10">

components/sections/__tests__/Disciplinas.test.tsx

@@ -1,4 +1,4 @@
-import { render, screen } from '@testing-library/react';
+import { render, screen, fireEvent } from '@testing-library/react';
 import { describe, it, expect } from 'vitest';
 import { Disciplinas } from '../Disciplinas';
 
@@ -16,4 +16,26 @@ describe('<Disciplinas />', () => {
     const items = list?.querySelectorAll('li');
     expect(items?.length).toBe(3);
   });
-});
+
+  it('lights the strand of the discipline being pointed at', () => {
+    const { container } = render(<Disciplinas />);
+    const tarjetas = container.querySelectorAll('ul > li');
+    expect(tarjetas).toHaveLength(3);
+
+    // Before anything is pointed at, the drawing is neutral.
+    const hebrasDoradas = () =>
+      Array.from(container.querySelectorAll('[data-hebra]')).filter((h) =>
+        (h.getAttribute('class') ?? '').includes('text-dorado'),
+      );
+    expect(hebrasDoradas()).toHaveLength(0);
+
+    // Pointing at "Digital", the second card, has to light the second strand
+    // and nothing else. This wiring is the whole change: without it the three
+    // cards and the drawing beside them are unrelated objects on a page.
+    fireEvent.pointerEnter(tarjetas[1]);
+    expect(hebrasDoradas().map((h) => h.getAttribute('data-hebra'))).toEqual(['1']);
+
+    fireEvent.pointerLeave(tarjetas[1]);
+    expect(hebrasDoradas()).toHaveLength(0);
+  });
+});