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/components/SiteBrandProvider.tsx

@@ -3,6 +3,7 @@
 import { createContext, useContext, useEffect, useMemo, useRef, useState, type ReactNode } from "react";
 import { apiGetSettings, type PublicSettings } from "@/lib/api";
 import { siteDocumentTitle, normalizeBrandLogoFit, normalizeBrandLogoSize, normalizeBrandMark, normalizeFooterLinks } from "@/lib/brand";
+import { normalizeUrlStyle, type UrlStyle } from "@/lib/urlStyle";
 import { realtime, RT_SETTINGS_CHANGED, type RtSettingsData } from "@/lib/realtime";
 import { onDocumentVisible, VISIBLE_RECONCILE_GAP_MS } from "@/lib/visibilityReconcile";
 
@@ -17,11 +18,12 @@ export type SiteBrand = {
   brand_logo_size: PublicSettings["brand_logo_size"];
   brand_logo_fit: PublicSettings["brand_logo_fit"];
   footer_links: PublicSettings["footer_links"];
+  url_style: UrlStyle;
 };
 
 const SiteBrandContext = createContext<SiteBrand | null>(null);
 
-function fromSettings(s: Pick<PublicSettings, keyof SiteBrand>): SiteBrand {
+function fromSettings(s: PublicSettings): SiteBrand {
   return {
     site_name: s.site_name,
     site_wordmark: s.site_wordmark,
@@ -33,6 +35,7 @@ function fromSettings(s: Pick<PublicSettings, keyof SiteBrand>): SiteBrand {
     brand_logo_size: s.brand_logo_size,
     brand_logo_fit: s.brand_logo_fit,
     footer_links: s.footer_links,
+    url_style: s.url_style,
   };
 }
 
@@ -47,6 +50,7 @@ function sameBrand(a: SiteBrand, b: SiteBrand): boolean {
     a.brand_mark === b.brand_mark &&
     a.brand_logo_size === b.brand_logo_size &&
     a.brand_logo_fit === b.brand_logo_fit &&
+    a.url_style === b.url_style &&
     JSON.stringify(a.footer_links) === JSON.stringify(b.footer_links)
   );
 }
@@ -97,11 +101,17 @@ export function useSiteBrand(): SiteBrand {
       brand_logo_size: "sq",
       brand_logo_fit: "contain",
       footer_links: [],
+      url_style: "default",
     };
   }
   return ctx;
 }
 
+/** 详情页伪静态风格（SSR 初值与水合一致，设置保存后 realtime 热更） */
+export function useUrlStyle(): UrlStyle {
+  return useSiteBrand().url_style;
+}
+
 /** SSR 初值 + settings:changed：页眉/页脚/标题/favicon 不必整页刷新 */
 export default function SiteBrandProvider({
   initial,
@@ -142,6 +152,7 @@ export default function SiteBrandProvider({
         footer_links: Array.isArray(raw.footer_links)
           ? normalizeFooterLinks(raw.footer_links)
           : prev.footer_links,
+        url_style: raw.url_style !== undefined ? normalizeUrlStyle(raw.url_style) : prev.url_style,
       };
       if (sameBrand(prev, next)) return;
       retitle(prev, next);