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/DashboardClient.tsx

@@ -10,7 +10,9 @@ import {
 } from "@/lib/api";
 import { postTypeLabel } from "@/lib/postMeta";
 import { formatRelative } from "@/lib/format";
+import { postPath, userPath } from "@/lib/urlStyle";
 import Avatar from "@/components/Avatar";
+import { useUrlStyle } from "@/components/SiteBrandProvider";
 import { AdminSegmented } from "@/components/admin";
 import {
   AdminChartCard,
@@ -67,6 +69,7 @@ export default function DashboardClient({
   totalUsers?: number;
   canUsers: boolean;
 }) {
+  const urlStyle = useUrlStyle();
   const [range, setRange] = useState<RangeKey>("7d");
   const [data, setData] = useState(initialAnalytics);
   const [error, setError] = useState<string | null>(null);
@@ -162,7 +165,7 @@ export default function DashboardClient({
             newUsers.slice(0, 8).map((u) => (
               <Link
                 key={u.id}
-                href={`/u/${u.id}`}
+                href={userPath(urlStyle, u.id)}
                 className="flex items-center gap-3 px-4 sm:px-5 py-3 transition-colors hover:bg-[var(--panel-2)]"
                 style={{ borderTop: "1px solid var(--line)" }}
               >
@@ -213,7 +216,7 @@ export default function DashboardClient({
             data.top_viewed.map((p, i) => (
               <Link
                 key={p.id}
-                href={`/post/${p.id}`}
+                href={postPath(urlStyle, p.id)}
                 className="flex items-center gap-3 px-4 sm:px-5 py-3 transition-colors hover:bg-[var(--panel-2)]"
                 style={{ borderTop: "1px solid var(--line)" }}
               >