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/lib/forum.ts

@@ -104,12 +104,24 @@ export async function getForum(id: number): Promise<{ name: string; description:
   }
 }
 
-export async function getTopics(forumId: number): Promise<Topic[]> {
+export async function countTopics(forumId: number): Promise<number> {
   try {
     const [rows] = await db(DB.web).query<RowDataPacket[]>(
-      'SELECT id, name, poster, created, sticky, locked, views FROM forum_topics WHERE forum_id = ? AND deleted = 0 ORDER BY sticky DESC, updated_at DESC, id DESC',
+      'SELECT COUNT(*) AS n FROM forum_topics WHERE forum_id = ? AND deleted = 0',
       [forumId],
     )
+    return Number(rows[0]?.n ?? 0)
+  } catch {
+    return 0
+  }
+}
+
+export async function getTopics(forumId: number, offset = 0, limit = 20): Promise<Topic[]> {
+  try {
+    const [rows] = await db(DB.web).query<RowDataPacket[]>(
+      'SELECT id, name, poster, created, sticky, locked, views FROM forum_topics WHERE forum_id = ? AND deleted = 0 ORDER BY sticky DESC, updated_at DESC, id DESC LIMIT ? OFFSET ?',
+      [forumId, limit, offset],
+    )
     return rows.map((r) => ({
       id: r.id,
       name: r.name,
@@ -146,12 +158,24 @@ export async function getTopic(id: number): Promise<TopicFull | null> {
   }
 }
 
-export async function getPosts(topicId: number): Promise<Post[]> {
+export async function countPosts(topicId: number): Promise<number> {
   try {
     const [rows] = await db(DB.web).query<RowDataPacket[]>(
-      'SELECT id, poster, poster_id, text, time, created_at, updated_at FROM forum_posts WHERE topic_id = ? AND deleted = 0 ORDER BY time ASC, id ASC',
+      'SELECT COUNT(*) AS n FROM forum_posts WHERE topic_id = ? AND deleted = 0',
       [topicId],
     )
+    return Number(rows[0]?.n ?? 0)
+  } catch {
+    return 0
+  }
+}
+
+export async function getPosts(topicId: number, offset = 0, limit = 15): Promise<Post[]> {
+  try {
+    const [rows] = await db(DB.web).query<RowDataPacket[]>(
+      'SELECT id, poster, poster_id, text, time, created_at, updated_at FROM forum_posts WHERE topic_id = ? AND deleted = 0 ORDER BY time ASC, id ASC LIMIT ? OFFSET ?',
+      [topicId, limit, offset],
+    )
     return rows.map((r) => ({
       id: r.id,
       poster: r.poster,