feat: 类型帖互动、积分经济与发帖体验

补齐问答采纳/重开、投票匿名与有票禁编、悬赏过期退回、抽奖回帖开奖，并接入积分账本与发帖附件可见性。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/app/board/[id]/page.tsx

@@ -77,7 +77,7 @@ export default async function BoardPage({ params, searchParams }: PageProps) {
               <p className="meta mt-1.5">{postsData.total} 篇讨论</p>
             </div>
           </div>
-          <Link href="/compose" className="btn btn-primary">
+          <Link href={`/compose?board=${id}`} className="btn btn-primary">
             <PenSquare size={15} /> 在此板块发帖
           </Link>
         </div>
@@ -117,7 +117,7 @@ export default async function BoardPage({ params, searchParams }: PageProps) {
                 </span>
                 <p className="font-bold text-lg" style={{ color: "var(--ink)" }}>该板块还没有帖子</p>
                 <p className="meta mt-1.5">来发第一篇，抢占沙发</p>
-                <Link href="/compose" className="btn btn-primary mt-6">
+                <Link href={`/compose?board=${id}`} className="btn btn-primary mt-6">
                   <PenSquare size={15} /> 写新帖
                 </Link>
               </div>