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/u/[id]/UserProfileContent.tsx

@@ -12,6 +12,8 @@ import { formatRelative } from "@/lib/format";
 import type {
   UserProfile, UserCommentsResponse, UserFavoritesResponse, UserFollowingResponse, PostListItem,
 } from "@/lib/api";
+import { postPath, userPath } from "@/lib/urlStyle";
+import { getPublicSettingsCached } from "@/lib/serverData";
 
 /** 本页卡片统一阴影；用 color-mix 让暗色主题自动加深，避免写死浅色阴影 */
 const CARD_SHADOW = "0 1px 3px color-mix(in srgb, #000 18%, transparent)";
@@ -26,11 +28,12 @@ const SORTS: { key: string; label: string }[] = [
 ];
 
 /** 帖子卡（发帖列表与收藏列表共用） */
-function PostCardItem({ post, allowComments }: { post: PostListItem; allowComments?: boolean }) {
+async function PostCardItem({ post, allowComments }: { post: PostListItem; allowComments?: boolean }) {
+  const urlStyle = (await getPublicSettingsCached()).url_style;
   const pinned = post.pinned > 0;
   return (
     <Link
-      href={`/post/${post.id}`}
+      href={postPath(urlStyle, post.id)}
       className={`${ITEM_BASE} ${
         pinned
           ? "bg-[color-mix(in_srgb,#fde68a_22%,var(--panel))] border-[color-mix(in_srgb,#fde68a_70%,var(--line))] hover:bg-[color-mix(in_srgb,#fde68a_30%,var(--panel))]"
@@ -139,7 +142,7 @@ function ErrorState({ retryHref }: { retryHref: string }) {
  * tab 与分页全部走 URL（?tab=xxx&page=N&sort=xxx），刷新/后退/分享链接均保持一致。
  * Tab 切换栏已移至 page.tsx 统一渲染（含 settings / security），此组件仅负责列表类 tab。
  */
-export default function UserProfileContent({
+export default async function UserProfileContent({
   userId,
   profile,
   tab,
@@ -168,6 +171,7 @@ export default function UserProfileContent({
   isOwner: boolean;
   allowComments?: boolean;
 }) {
+  const urlStyle = (await getPublicSettingsCached()).url_style;
   const displayName = profile.user.nickname || profile.user.username;
   const paginationQuery: Record<string, string> =
     tab === "comments" ? { tab: "comments" }
@@ -189,7 +193,7 @@ export default function UserProfileContent({
               {SORTS.map((s) => (
                 <Link
                   key={s.key}
-                  href={s.key === "new" ? `/u/${userId}` : `/u/${userId}?sort=${s.key}`}
+                  href={s.key === "new" ? userPath(urlStyle, Number(userId)) : `${userPath(urlStyle, Number(userId))}?sort=${s.key}`}
                   className="j13-chip"
                   aria-current={sort === s.key ? "page" : undefined}
                 >
@@ -215,13 +219,13 @@ export default function UserProfileContent({
             total={profile.posts_total}
             page={page}
             size={20}
-            basePath={`/u/${userId}`}
+            basePath={userPath(urlStyle, Number(userId))}
             query={paginationQuery}
           />
         </div>
       ) : tab === "favorites" ? (
         favoriteError ? (
-          <ErrorState retryHref={`/u/${userId}?tab=favorites`} />
+          <ErrorState retryHref={`${userPath(urlStyle, Number(userId))}?tab=favorites`} />
         ) : favoriteData && favoriteData.posts.length > 0 ? (
           <div>
             <div className="mb-3 flex flex-wrap items-center justify-between gap-2">
@@ -238,7 +242,7 @@ export default function UserProfileContent({
               total={favoriteData.total}
               page={favoriteData.page}
               size={20}
-              basePath={`/u/${userId}`}
+              basePath={userPath(urlStyle, Number(userId))}
               query={paginationQuery}
             />
           </div>
@@ -250,7 +254,7 @@ export default function UserProfileContent({
         )
       ) : tab === "following" ? (
         followingError ? (
-          <ErrorState retryHref={`/u/${userId}?tab=following`} />
+          <ErrorState retryHref={`${userPath(urlStyle, Number(userId))}?tab=following`} />
         ) : followingData && followingData.users.length > 0 ? (
           <div>
             <div className="mb-3 flex flex-wrap items-center justify-between gap-2">
@@ -265,7 +269,7 @@ export default function UserProfileContent({
                   className="group flex items-center gap-3 rounded-xl border px-5 py-4 transition-[background-color,box-shadow,border-color] duration-150 bg-[var(--panel)] border-[var(--line)] hover:bg-[color-mix(in_srgb,var(--ink)_3.5%,var(--panel))]"
                   style={{ boxShadow: CARD_SHADOW }}
                 >
-                  <Link href={`/u/${fu.id}`} className="flex min-w-0 flex-1 items-center gap-3">
+                  <Link href={userPath(urlStyle, fu.id)} className="flex min-w-0 flex-1 items-center gap-3">
                     <Avatar name={fu.nickname || fu.username} src={fu.avatar || undefined} size={40} />
                     <div className="min-w-0">
                       <div className="flex items-center gap-1.5">
@@ -291,7 +295,7 @@ export default function UserProfileContent({
               total={followingData.total}
               page={followingData.page}
               size={20}
-              basePath={`/u/${userId}`}
+              basePath={userPath(urlStyle, Number(userId))}
               query={paginationQuery}
             />
           </div>
@@ -302,14 +306,14 @@ export default function UserProfileContent({
           />
         )
       ) : commentError ? (
-        <ErrorState retryHref={`/u/${userId}?tab=comments`} />
+        <ErrorState retryHref={`${userPath(urlStyle, Number(userId))}?tab=comments`} />
       ) : commentData && (commentData.comments?.length ?? 0) > 0 ? (
         <div>
           <div className="panel overflow-hidden">
             {(commentData.comments ?? []).map((c) => (
               <Link
                 key={c.id}
-                href={`/post/${c.post_id}#comment-${c.id}`}
+                href={`${postPath(urlStyle, c.post_id)}#comment-${c.id}`}
                 className="group block px-4 sm:px-5 py-4 border-t transition-colors hover:bg-[var(--item-hover-bg)] focus-visible:bg-[var(--item-hover-bg)]"
                 style={{ borderColor: "var(--line)" }}
               >
@@ -335,7 +339,7 @@ export default function UserProfileContent({
             total={commentData.total}
             page={commentData.page}
             size={20}
-            basePath={`/u/${userId}`}
+            basePath={userPath(urlStyle, Number(userId))}
             query={paginationQuery}
           />
         </div>