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/points/EconomyOverview.tsx

@@ -9,6 +9,8 @@ import { pointReasonLabel } from "@/lib/points";
 import { formatRelative } from "@/lib/format";
 import { AdminPageHeader, AdminSegmented, AdminStatCard } from "@/components/admin";
 import Avatar from "@/components/Avatar";
+import { useUrlStyle } from "@/components/SiteBrandProvider";
+import { userPath } from "@/lib/urlStyle";
 import {
   AdminChartCard,
   DeltaBarChart,
@@ -326,10 +328,11 @@ function StockOverviewCard({ stats }: { stats: EconomyStats }) {
 }
 
 function LedgerUserLink({ user, compact }: { user: LedgerParty; compact?: boolean }) {
+  const urlStyle = useUrlStyle();
   const name = partyName(user);
   return (
     <Link
-      href={`/u/${user.id}`}
+      href={userPath(urlStyle, user.id)}
       className="flex items-center gap-1.5 min-w-0 max-w-[128px] rounded-md hover:bg-[var(--panel-2)] -mx-0.5 px-0.5 py-0.5 transition-colors"
       title={`${name} @${user.username}`}
     >

frontend/app/admin/points/UserPointsTab.tsx

@@ -17,6 +17,8 @@ import { AdminPageHeader, AdminPager, AdminSearchField, AdminStepper } from "@/c
 import { pointReasonLabel } from "@/lib/points";
 import { formatRelative } from "@/lib/format";
 import { toast } from "@/lib/toast";
+import { userPath } from "@/lib/urlStyle";
+import { useUrlStyle } from "@/components/SiteBrandProvider";
 
 const PAGE_SIZE = 20;
 const MAX_DELTA = 100000; // 与后端 adminAdjustMaxDelta 一致
@@ -72,6 +74,7 @@ function SortHeader({
  * 扣分仅扣余额不降级，理由必填）与「流水」弹窗（分页查看该用户积分流水）。
  */
 export default function UserPointsTab() {
+  const urlStyle = useUrlStyle();
   const [keyword, setKeyword] = useState("");
   const [appliedQ, setAppliedQ] = useState("");
   const [page, setPage] = useState(1);
@@ -209,7 +212,7 @@ export default function UserPointsTab() {
               {users.map((u) => (
                 <tr key={u.id} style={{ borderBottom: "1px solid var(--line)" }}>
                   <td className="px-4 py-2.5">
-                    <Link href={`/u/${u.id}`} className="flex items-center gap-2.5 min-w-0 group">
+                    <Link href={userPath(urlStyle, u.id)} className="flex items-center gap-2.5 min-w-0 group">
                       <Avatar name={u.nickname || u.username} src={u.avatar || undefined} size={30} />
                       <span className="min-w-0">
                         <span