feat: 可配置站点 URL 风格

- 新增 urlStyle 工具与测试：postPath/userPath/sitePagePath 统一生成链接
- 管理端新增 UrlStylePanel 设置面板，settings 服务与 handler 适配
- 全站路由链接与 JSON-LD/sitemap 切换为统一 URL 生成
- middleware 与相关组件适配

frontend/components/ChatUserCard.tsx

@@ -11,6 +11,8 @@ import LevelBadge from "@/components/LevelBadge";
 import BadgeChip from "@/components/BadgeChip";
 import ImageLightbox from "@/components/markdown/ImageLightbox";
 import { useAllowMessages } from "@/components/MessagesPolicyProvider";
+import { useUrlStyle } from "@/components/SiteBrandProvider";
+import { userPath } from "@/lib/urlStyle";
 import { apiGetUserProfile, apiOpenDirectChat, type UserProfile, type User } from "@/lib/api";
 import { toast } from "@/lib/toast";
 
@@ -36,6 +38,7 @@ export default function ChatUserCard({
 }) {
   const router = useRouter();
   const allowMessages = useAllowMessages();
+  const urlStyle = useUrlStyle();
   const [profile, setProfile] = useState<UserProfile | null>(null);
   const [dmBusy, setDmBusy] = useState(false);
   const [avatarOpen, setAvatarOpen] = useState(false);
@@ -194,7 +197,7 @@ export default function ChatUserCard({
 
         {/* 操作区 */}
         <div className="mt-4 flex items-center gap-2">
-          <Link href={`/u/${user.id}`} className="btn btn-line btn-sm flex-1 justify-center">
+          <Link href={userPath(urlStyle, user.id)} className="btn btn-line btn-sm flex-1 justify-center">
             用户主页
           </Link>
           {allowMessages && !isSelf && (