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/sitemap.ts

@@ -6,6 +6,8 @@ import {
   fetchPublishedSitePages,
 } from "@/lib/api";
 import { canonicalPath, resolveSiteOrigin } from "@/lib/siteUrl";
+import { announcementPath, postPath, pagePath, leaderboardPath } from "@/lib/urlStyle";
+import { getPublicSettingsCached } from "@/lib/serverData";
 
 export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
   await connection();
@@ -14,6 +16,7 @@ export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
     console.error("[seo] SITE_URL 缺失或非法，已跳过 sitemap");
     return [];
   }
+  const style = (await getPublicSettingsCached()).url_style;
 
   const url = (pathname: string) => `${origin}${canonicalPath(pathname)}`;
   const entries: MetadataRoute.Sitemap = [
@@ -25,7 +28,7 @@ export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
       priority: 0.7,
     },
     {
-      url: url("/leaderboard"),
+      url: url(leaderboardPath(style)),
       lastModified: new Date(),
       changeFrequency: "daily",
       priority: 0.5,
@@ -42,7 +45,7 @@ export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
     const { posts } = await fetchPosts(1, 100);
     for (const post of posts) {
       entries.push({
-        url: url(`/post/${post.id}`),
+        url: url(postPath(style, post.id)),
         lastModified: new Date(post.created_at),
         changeFrequency: "weekly",
         priority: 0.6,
@@ -56,7 +59,7 @@ export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
     const { announcements } = await fetchAnnouncementsPage(1, 100);
     for (const a of announcements) {
       entries.push({
-        url: url(`/announcement/${a.id}`),
+        url: url(announcementPath(style, a.id)),
         lastModified: new Date(a.updated_at || a.created_at),
         changeFrequency: "weekly",
         priority: 0.5,
@@ -70,7 +73,7 @@ export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
     const { pages } = await fetchPublishedSitePages();
     for (const p of pages) {
       entries.push({
-        url: url(`/p/${p.slug}`),
+        url: url(pagePath(style, p.slug)),
         lastModified: new Date(p.updated_at || p.created_at),
         changeFrequency: "monthly",
         priority: 0.4,