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/components/AvatarPicker.tsx

@@ -69,8 +69,8 @@ export default function AvatarPicker({
         onClick={() => setOpen(true)}
         className="group relative inline-flex items-center justify-center shrink-0 p-0 rounded-full cursor-pointer outline-none focus-visible:ring-2 focus-visible:ring-[var(--accent)] focus-visible:ring-offset-2 focus-visible:ring-offset-[var(--panel)]"
         style={{ width: size, height: size, lineHeight: 0 }}
+        data-tip="更换头像"
         aria-label="更换头像"
-        title="更换头像"
       >
         <Avatar name={name} src={current || undefined} size={size} />
         {/* hover/focus 遮罩：与头像严格重合（按钮宽高固定 = size） */}