feat(posts): 类型帖截止时间、抽奖奖品表与悬赏发帖体验

统一投票/悬赏/抽奖截止与状态展示，抽奖支持多奖品行；发帖页悬赏积分对齐表格输入，并在余额不足时于底部就地提示。

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

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

@@ -714,8 +714,11 @@ export default async function PostDetailPage({ params, searchParams }: PageProps
                 <AcceptedAnswerCard
                   answer={acceptedAnswer}
                   variant={acceptedAnswerVariant}
-                  postId={post.id}
-                  canReopen={!!post.question?.can_reopen}
+                  solvedAt={
+                    post.question?.solved_at ||
+                    post.bounty?.accepted_answer?.created_at ||
+                    acceptedAnswer.created_at
+                  }
                 />
               ) : questionState ? (
                 <QuestionStatusCard postId={post.id} state={questionState} />