feat: 用户徽章与等级体系，积分经济管理重构

- 新增徽章系统：badge 服务与 handler、管理端配置页、BadgeChip/LevelBadge 展示组件
- 新增等级模型：model/level 及前端 levels 元数据
- 管理端经济模块拆分为 points/badges/levels 独立页面，EconomySettings 迁入设置
- 积分、签到、评论等服务适配等级与徽章逻辑

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

@@ -32,6 +32,8 @@ import { SiteDocBreadcrumb } from "@/components/site-doc";
 import MobilePostBar from "@/components/MobilePostBar";
 import Avatar from "@/components/Avatar";
 import RoleBadge from "@/components/RoleBadge";
+import LevelBadge from "@/components/LevelBadge";
+import BadgeChip from "@/components/BadgeChip";
 import MarkdownBody from "@/components/MarkdownBody";
 import { publicMarkdownForSeo } from "@/lib/hideBlocks";
 import PostAttachments from "@/components/PostAttachments";
@@ -185,6 +187,10 @@ function AuthorCardStacked({
             >
               {u.nickname}
             </Link>
+            <LevelBadge level={u.level} />
+            {(u.badges ?? []).slice(0, 2).map((ub) => (
+              <BadgeChip key={ub.id} badge={ub.badge} />
+            ))}
             {u.role !== "user" && <RoleBadge role={u.role} boardIds={u.board_ids} />}
           </div>
           <p className="meta mt-1 flex items-center gap-1.5 flex-wrap">