feat: 友链/书库/移动端导航/排行榜等多模块功能

新增模块：
- 友链（friendlink）后端处理 + 前端管理页与友链板
- 书库（library）：导入、章节、封面、阅读页、横竖版自适应 AdaptiveCoverSlot
- 顶栏导航（header_nav）配置与 MobileTabBar/MobileRailDrawers 移动端抽屉
- 排行榜 service 测试、站点页面测试、时间线发布（timeline_release）

其它改动：
- 后端 handlers/services 全量小幅调整
- 前端组件、库函数、URL/品牌/站点 URL 工具更新
- Lightbox 图片、MdEntries 条目卡、coverColor 派生色相等前端能力

frontend/app/sitemap.ts

@@ -4,9 +4,10 @@ import {
   fetchPosts,
   fetchAnnouncementsPage,
   fetchPublishedSitePages,
+  fetchLibraryList,
 } from "@/lib/api";
 import { canonicalPath, resolveSiteOrigin } from "@/lib/siteUrl";
-import { announcementPath, postPath, pagePath, leaderboardPath } from "@/lib/urlStyle";
+import { announcementPath, postPath, pagePath, leaderboardPath, libraryPath, libraryDocPath } from "@/lib/urlStyle";
 import { getPublicSettingsCached } from "@/lib/serverData";
 
 export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
@@ -33,6 +34,12 @@ export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
       changeFrequency: "daily",
       priority: 0.5,
     },
+    {
+      url: url(libraryPath(style)),
+      lastModified: new Date(),
+      changeFrequency: "daily",
+      priority: 0.5,
+    },
     {
       url: url("/about"),
       lastModified: new Date(),
@@ -83,5 +90,19 @@ export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
     /* 忽略 */
   }
 
+  try {
+    const { docs } = await fetchLibraryList();
+    for (const d of docs) {
+      entries.push({
+        url: url(libraryDocPath(style, d.slug)),
+        lastModified: new Date(d.updated_at || d.created_at),
+        changeFrequency: "weekly",
+        priority: 0.4,
+      });
+    }
+  } catch {
+    /* 忽略 */
+  }
+
   return entries;
 }