Foro (lectura): índice, temas y mensajes en Next.js

- lib/forum.ts: getForumIndex (categorías + foros visibles con contadores y último
  tema, port de forum/db.py), getForum/getTopics, getTopic/getPosts (acore_web).
- Páginas app/[locale]/forum (índice), /forum/[forumId] (temas), /forum/topic/[topicId]
  (mensajes; render del HTML ya saneado por Django). Enlace "Foros" en la cabecera.
- Catálogo Forum + Nav.forum.

Verificado: /forum 200, foros/temas inexistentes 404, enlace en la cabecera.
Solo lectura; pendiente escribir (crear tema/responder + saneado nh3->TS) y moderación.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-next/app/[locale]/forum/topic/[topicId]/page.tsx

@@ -0,0 +1,52 @@
+import { notFound } from 'next/navigation'
+import { getTranslations, setRequestLocale } from 'next-intl/server'
+import { Link } from '@/i18n/navigation'
+import { getTopic, getPosts } from '@/lib/forum'
+
+export const dynamic = 'force-dynamic'
+
+export default async function TopicPage({
+  params,
+}: {
+  params: Promise<{ locale: string; topicId: string }>
+}) {
+  const { locale, topicId } = await params
+  setRequestLocale(locale)
+  const t = await getTranslations('Forum')
+
+  const id = Number(topicId)
+  const topic = await getTopic(id)
+  if (!topic) notFound()
+  const posts = await getPosts(id)
+
+  return (
+    <main className="mx-auto max-w-4xl px-4 py-8">
+      <p className="mb-2 text-sm">
+        <Link href="/forum" className="text-sky-400 hover:underline">
+          ← {t('backToForum')}
+        </Link>
+      </p>
+      <h1 className="mb-6 text-2xl font-bold text-amber-500">
+        {topic!.locked && <span className="mr-2 text-sm text-red-400">[{t('locked')}]</span>}
+        {topic!.name}
+      </h1>
+
+      <div className="space-y-4">
+        {posts.map((post) => (
+          <article key={post.id} className="rounded-lg border border-amber-900/60 bg-[#241812] p-4">
+            <div className="mb-2 flex items-center justify-between border-b border-amber-900/40 pb-2 text-sm">
+              <span className="font-semibold text-amber-400">{post.poster}</span>
+              {post.time && (
+                <span className="text-amber-200/50">{new Date(post.time).toLocaleString(locale)}</span>
+              )}
+            </div>
+            <div
+              className="prose prose-invert max-w-none text-sm"
+              dangerouslySetInnerHTML={{ __html: post.text }}
+            />
+          </article>
+        ))}
+      </div>
+    </main>
+  )
+}