Foro: paginación de temas (20/pág) y de posts (15/pág)

- lib/forum.ts: countTopics/countPosts + offset/limit en getTopics/getPosts
  (mismos límites que Django: FORUM_TOPICS_PER_PAGE=20, FORUM_POSTS_PER_PAGE=15).
- components/Pagination.tsx: paginación reutilizable (ventana ±2, primera/última,
  prev/next) con enlaces ?page=N; no renderiza si solo hay una página.
- Foro y tema aceptan ?page=N (clamp al rango válido).
- El formulario de respuesta solo aparece en la última página; enlace a ella si no.
- i18n: namespace Common (prev/next/page) + replyOnLastPage.

Build OK. Sin datos de foro en acore_web (estado vacío correcto).

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

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

@@ -1,19 +1,24 @@
 import { notFound } from 'next/navigation'
 import { getTranslations, setRequestLocale } from 'next-intl/server'
 import { Link } from '@/i18n/navigation'
-import { getTopic, getPosts } from '@/lib/forum'
+import { getTopic, getPosts, countPosts } from '@/lib/forum'
 import { getSession } from '@/lib/session'
 import { forumIsModerator, canEditPost } from '@/lib/forum-perm'
 import { ReplyForm } from '@/components/ReplyForm'
 import { PostActions } from '@/components/PostActions'
 import { TopicModBar } from '@/components/TopicModBar'
+import { Pagination } from '@/components/Pagination'
 
 export const dynamic = 'force-dynamic'
 
+const PER_PAGE = 15
+
 export default async function TopicPage({
   params,
+  searchParams,
 }: {
   params: Promise<{ locale: string; topicId: string }>
+  searchParams: Promise<{ page?: string }>
 }) {
   const { locale, topicId } = await params
   setRequestLocale(locale)
@@ -22,7 +27,10 @@ export default async function TopicPage({
   const id = Number(topicId)
   const topic = await getTopic(id)
   if (!topic) notFound()
-  const posts = await getPosts(id)
+  const total = await countPosts(id)
+  const totalPages = Math.max(1, Math.ceil(total / PER_PAGE))
+  const page = Math.min(Math.max(1, Number((await searchParams).page) || 1), totalPages)
+  const posts = await getPosts(id, (page - 1) * PER_PAGE, PER_PAGE)
   const session = await getSession()
   const isMod = await forumIsModerator(session)
   const canReply = Boolean(session.username) && (!topic!.locked || isMod)
@@ -65,8 +73,18 @@ export default async function TopicPage({
         ))}
       </div>
 
+      <Pagination page={page} totalPages={totalPages} hrefFor={(p) => `/forum/topic/${id}?page=${p}`} />
+
       {canReply ? (
-        <ReplyForm topicId={id} />
+        page === totalPages ? (
+          <ReplyForm topicId={id} />
+        ) : (
+          <p className="mt-6 text-sm">
+            <Link href={`/forum/topic/${id}?page=${totalPages}`} className="text-sky-400 hover:underline">
+              {t('replyOnLastPage')}
+            </Link>
+          </p>
+        )
       ) : (
         !session.username && <p className="mt-6 text-sm text-amber-200/60">{t('loginToPost')}</p>
       )}