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/about/page.tsx

@@ -18,6 +18,7 @@ import {
   SiteDocAnnoNav,
 } from "@/components/site-doc";
 import { requestCanonical } from "@/lib/canonicalMeta";
+import { pagePath, type UrlStyle } from "@/lib/urlStyle";
 
 export async function generateMetadata(): Promise<Metadata> {
   return {
@@ -30,14 +31,16 @@ export async function generateMetadata(): Promise<Metadata> {
 function PageRow({
   p,
   showDivider,
+  urlStyle,
 }: {
   p: SitePageSummary;
   showDivider: boolean;
+  urlStyle: UrlStyle;
 }) {
   const Icon = pageGlyph(p.slug);
   return (
     <Link
-      href={`/p/${p.slug}`}
+      href={pagePath(urlStyle, p.slug)}
       className="block px-5 sm:px-6 py-4 sm:py-5 transition-colors hover:bg-[var(--panel-2)] focus-visible:bg-[var(--panel-2)]"
       style={showDivider ? { borderTop: "1px solid var(--line)" } : undefined}
     >
@@ -90,6 +93,7 @@ export default async function AboutIndexPage() {
   ]);
   const announcements = overview?.announcements ?? [];
   const siteLead = settings.site_description?.trim() || undefined;
+  const urlStyle = settings.url_style;
   const canManagePages = !!me.user && isAdminOrAbove(me.user.role);
 
   const left = <SiteDocIdentity kind="about" lead={siteLead} />;
@@ -146,7 +150,7 @@ export default async function AboutIndexPage() {
             <p className="meta mt-1.5">有新文档时会显示在这里</p>
           </div>
         ) : (
-          pages.map((p, i) => <PageRow key={p.id} p={p} showDivider={i > 0} />)
+          pages.map((p, i) => <PageRow key={p.id} p={p} showDivider={i > 0} urlStyle={urlStyle} />)
         )}
       </div>
     </SiteDocShell>