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/app/admin/users/UsersAdmin.tsx

@@ -36,6 +36,8 @@ import {
 import { isOwner, ROLES } from "@/lib/roles";
 import { formatDate, formatRelative } from "@/lib/format";
 import { realtime } from "@/lib/realtime";
+import { userPath } from "@/lib/urlStyle";
+import { useUrlStyle } from "@/components/SiteBrandProvider";
 import Avatar from "@/components/Avatar";
 import RoleBadge from "@/components/RoleBadge";
 import Modal from "@/components/Modal";
@@ -302,6 +304,7 @@ export default function UsersAdmin({
   currentUserId: number;
   currentUserRole: string;
 }) {
+  const urlStyle = useUrlStyle();
   const [users, setUsers] = useState<AdminUser[]>(initial?.users ?? []);
   const [summary, setSummary] = useState<AdminUserSummary>(
     initial?.summary ?? {
@@ -686,7 +689,7 @@ export default function UsersAdmin({
       return (
         <div className="flex items-center gap-1.5 flex-wrap">
           {auditBtn}
-          <Link href={`/u/${u.id}`} className="btn btn-line btn-sm gap-1" aria-label={`查看 ${u.nickname} 的个人主页`}>
+          <Link href={userPath(urlStyle, u.id)} className="btn btn-line btn-sm gap-1" aria-label={`查看 ${u.nickname} 的个人主页`}>
             <ExternalLink size={13} />
             主页
           </Link>
@@ -697,7 +700,7 @@ export default function UsersAdmin({
       return (
         <div className="flex items-center gap-1.5 flex-wrap">
           {auditBtn}
-          <Link href={`/u/${u.id}`} className="btn btn-line btn-sm gap-1" aria-label={`查看 ${u.nickname} 的个人主页`}>
+          <Link href={userPath(urlStyle, u.id)} className="btn btn-line btn-sm gap-1" aria-label={`查看 ${u.nickname} 的个人主页`}>
             <ExternalLink size={13} />
             主页
           </Link>
@@ -718,7 +721,7 @@ export default function UsersAdmin({
     return (
       <div className="flex items-center gap-1.5 flex-wrap">
         {auditBtn}
-        <Link href={`/u/${u.id}`} className="btn btn-line btn-sm gap-1" aria-label={`查看 ${u.nickname} 的个人主页`}>
+        <Link href={userPath(urlStyle, u.id)} className="btn btn-line btn-sm gap-1" aria-label={`查看 ${u.nickname} 的个人主页`}>
           <ExternalLink size={13} />
           主页
         </Link>

frontend/app/admin/users/[id]/UserAuditClient.tsx

@@ -14,7 +14,9 @@ import {
 } from "@/lib/api";
 import { formatDate, formatRelative } from "@/lib/format";
 import Avatar from "@/components/Avatar";
+import { useUrlStyle } from "@/components/SiteBrandProvider";
 import RoleBadge from "@/components/RoleBadge";
+import { postPath, userPath } from "@/lib/urlStyle";
 import {
   AdminEmpty,
   AdminPager,
@@ -72,6 +74,7 @@ export default function UserAuditClient({
   initialPostsTotal: number;
   initError: string;
 }) {
+  const urlStyle = useUrlStyle();
   const [profile] = useState(initial);
   const [tab, setTab] = useState<TabKey>("posts");
   const [loading, setLoading] = useState(false);
@@ -231,7 +234,7 @@ export default function UserAuditClient({
             </p>
           </div>
           <Link
-            href={`/u/${u.id}`}
+            href={userPath(urlStyle, u.id)}
             className="btn btn-line btn-sm gap-1.5 shrink-0"
             target="_blank"
           >
@@ -318,7 +321,7 @@ export default function UserAuditClient({
                     </p>
                   ) : (
                     <Link
-                      href={`/post/${p.id}`}
+                      href={postPath(urlStyle, p.id)}
                       className="text-[14px] font-medium hover:underline"
                       style={{ color: "var(--ink)" }}
                     >
@@ -353,7 +356,7 @@ export default function UserAuditClient({
                       <span className="text-[11.5px] meta">帖子 #{c.post_id}</span>
                     ) : (
                       <Link
-                        href={`/post/${c.post_id}#comment-${c.id}`}
+                        href={`${postPath(urlStyle, c.post_id)}#comment-${c.id}`}
                         className="text-[11.5px] hover:underline"
                         style={{ color: "var(--accent)" }}
                       >