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/settings/BasicSettings.tsx

@@ -6,6 +6,7 @@ import useUnsavedGuard from "@/hooks/useUnsavedGuard";
 import BasicIdentityPanel from "./BasicIdentityPanel";
 import BrandSeoPanel from "./BrandSeoPanel";
 import FooterLinksPanel from "./FooterLinksPanel";
+import UrlStylePanel from "./UrlStylePanel";
 import type { PublicSettings } from "@/lib/api";
 
 export default function BasicSettings({ initial }: { initial: PublicSettings }) {
@@ -13,17 +14,20 @@ export default function BasicSettings({ initial }: { initial: PublicSettings })
   const [basicDirty, setBasicDirty] = useState(false);
   const [brandDirty, setBrandDirty] = useState(false);
   const [seoDirty, setSeoDirty] = useState(false);
-  const dirty = basicDirty || brandDirty || seoDirty;
+  const [urlStyleDirty, setUrlStyleDirty] = useState(false);
+  const dirty = basicDirty || brandDirty || seoDirty || urlStyleDirty;
   const leave = useUnsavedGuard(dirty);
 
   const onBasicDirty = useCallback((d: boolean) => setBasicDirty(d), []);
   const onBrandDirty = useCallback((d: boolean) => setBrandDirty(d), []);
   const onSeoDirty = useCallback((d: boolean) => setSeoDirty(d), []);
+  const onUrlStyleDirty = useCallback((d: boolean) => setUrlStyleDirty(d), []);
 
   return (
     <div className="admin-settings-stack">
       <BasicIdentityPanel initial={live} onSaved={setLive} onDirtyChange={onBasicDirty} />
       <BrandSeoPanel initial={live} onSaved={setLive} onDirtyChange={onBrandDirty} />
+      <UrlStylePanel initial={live} onSaved={setLive} onDirtyChange={onUrlStyleDirty} />
       <FooterLinksPanel initial={live} onSaved={setLive} onDirtyChange={onSeoDirty} />
       <ConfirmDialog
         open={leave.leaveOpen}

frontend/app/admin/settings/UrlStylePanel.tsx

@@ -0,0 +1,123 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { AdminSettingsActions, AdminSettingsGroup } from "@/components/admin";
+import { apiUpdateSiteSettings, type PublicSettings } from "@/lib/api";
+import { announcementPath, leaderboardPath, pagePath, postPath, userPath, type UrlStyle } from "@/lib/urlStyle";
+import { toast } from "@/lib/toast";
+
+/** 三档风格展示信息：示例 id/slug 固定，方便站长对比形态 */
+const STYLE_OPTIONS: { value: UrlStyle; label: string; desc: string }[] = [
+  { value: "default", label: "标准动态", desc: "框架默认路由，带路径分段" },
+  { value: "html", label: "静态页 .html", desc: "常见 CMS 伪静态形态" },
+  { value: "discuz", label: "Discuz 风格", desc: "经典论坛 thread- 形态" },
+];
+
+function samplePaths(style: UrlStyle) {
+  return [
+    { kind: "帖子", path: postPath(style, 123) },
+    { kind: "用户", path: userPath(style, 5) },
+    { kind: "公告", path: announcementPath(style, 1) },
+    { kind: "自建页", path: pagePath(style, "about") },
+    { kind: "排行榜", path: leaderboardPath(style) },
+  ];
+}
+
+export default function UrlStylePanel({
+  initial,
+  onSaved,
+  onDirtyChange,
+}: {
+  initial: PublicSettings;
+  onSaved?: (next: PublicSettings) => void;
+  onDirtyChange?: (dirty: boolean) => void;
+}) {
+  const [style, setStyle] = useState<UrlStyle>(initial.url_style);
+  const [savedStyle, setSavedStyle] = useState<UrlStyle>(initial.url_style);
+  const [saving, setSaving] = useState(false);
+  const [error, setError] = useState("");
+
+  const dirty = style !== savedStyle;
+
+  useEffect(() => {
+    onDirtyChange?.(dirty);
+  }, [dirty, onDirtyChange]);
+
+  const discard = () => {
+    setStyle(savedStyle);
+    setError("");
+  };
+
+  const save = async () => {
+    if (saving || !dirty) return;
+    setSaving(true);
+    setError("");
+    try {
+      const res = await apiUpdateSiteSettings({ url_style: style });
+      setSavedStyle(res.url_style);
+      setStyle(res.url_style);
+      onSaved?.(res);
+      toast("已保存，全站链接风格已切换", "ok");
+    } catch (e) {
+      const msg = e instanceof Error ? e.message : "保存失败";
+      setError(msg);
+      toast(msg);
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  return (
+    <AdminSettingsGroup
+      id="settings-url-style"
+      title="链接风格（伪静态）"
+      description="帖子、用户主页、公告等详情页的 URL 形态。"
+      footer={
+        <AdminSettingsActions
+          dirty={dirty}
+          saving={saving}
+          saveLabel="保存"
+          error={error}
+          onSave={() => void save()}
+          onDiscard={discard}
+        />
+      }
+    >
+      <div className="grid gap-3 sm:grid-cols-3" role="radiogroup" aria-label="链接风格">
+        {STYLE_OPTIONS.map((opt) => {
+          const on = style === opt.value;
+          return (
+            <button
+              key={opt.value}
+              type="button"
+              role="radio"
+              aria-checked={on}
+              className={`admin-url-style-card${on ? " is-on" : ""}`}
+              onClick={() => setStyle(opt.value)}
+            >
+              <span className="flex items-center justify-between gap-2">
+                <span className="text-[13.5px] font-semibold">{opt.label}</span>
+                <span className={`admin-url-style-dot${on ? " is-on" : ""}`} aria-hidden />
+              </span>
+              <span className="meta mt-0.5 block text-[11.5px]">{opt.desc}</span>
+              <span className="admin-url-style-examples">
+                {samplePaths(opt.value).map((s) => (
+                  <span key={s.kind} className="admin-url-style-example">
+                    <span className="meta">{s.kind}</span>
+                    <code>{s.path}</code>
+                  </span>
+                ))}
+              </span>
+            </button>
+          );
+        })}
+      </div>
+
+      <ul className="admin-url-style-notes meta mt-3 text-[12px]">
+        <li>保存后全站前台链接立即按新风格生成；旧风格链接自动 301 到新风格，收录与外链不断链。</li>
+        <li>301 会被浏览器长期缓存，切换前请想清楚；建议长期固定一种风格，不要频繁来回切换。</li>
+        <li>自建页与排行榜同样参与伪静态；自建页 slug 含中文时自动 URL 编码，地址栏多数浏览器仍显示中文。</li>
+      </ul>
+    </AdminSettingsGroup>
+  );
+}