Foro: mover tema entre foros (moderadores)

- lib/forum-write.ts: moveTopic (forum_id + moved=1). lib/forum.ts: listForumsForMove.
- API /api/forum/moderate: acción 'move' con forumId, validando foro destino visible
  y distinto del actual.
- TopicModBar: selector «Mover a» con los foros visibles (excl. el actual); tras mover,
  redirige al foro destino.
- i18n es/en: Forum.moveTopic.

Verificado: build OK, move 401 sin sesión, /forum 200.

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

web-next/app/api/forum/moderate/route.ts

@@ -1,9 +1,9 @@
 import { getSession } from '@/lib/session'
-import { getTopic } from '@/lib/forum'
-import { setTopicFlag } from '@/lib/forum-write'
+import { getTopic, getForum } from '@/lib/forum'
+import { setTopicFlag, moveTopic } from '@/lib/forum-write'
 import { forumIsModerator } from '@/lib/forum-perm'
 
-type Action = 'lock' | 'unlock' | 'sticky' | 'unsticky' | 'delete'
+type Action = 'lock' | 'unlock' | 'sticky' | 'unsticky' | 'delete' | 'move'
 
 /** Moderación de temas: bloquear, fijar, borrar. Solo moderadores. */
 export async function POST(request: Request) {
@@ -36,6 +36,17 @@ export async function POST(request: Request) {
     case 'delete':
       await setTopicFlag(topicId, 'deleted', true)
       return Response.json({ success: true, forumId: topic.forum_id })
+    case 'move': {
+      const newForumId = Number(b.forumId)
+      if (!newForumId || newForumId === topic.forum_id) {
+        return Response.json({ success: false, error: 'invalidRequest' }, { status: 400 })
+      }
+      if (!(await getForum(newForumId))) {
+        return Response.json({ success: false, error: 'invalidForum' }, { status: 400 })
+      }
+      await moveTopic(topicId, newForumId)
+      return Response.json({ success: true })
+    }
     default:
       return Response.json({ success: false, error: 'invalidRequest' }, { status: 400 })
   }