feat: 书库导入导出/图片变体/书籍搜索/小组件运行时等

新增：
- 书库导入导出（library_import/library_export）及测试
- 图片变体生成（image_variants）与响应式图片（responsiveImage）
- 书籍搜索（bookSearch）+ BookSearch/LibrarySearchGrid 组件
- 小组件运行时（widgetRuntime）与静态检查（widgetLint）
- 上传缓存中间件（upload_cache）与字体 CSS 提取脚本

其它：
- 后端 handlers/services 全量调整
- 前端页面、组件、库函数与配置更新

frontend/app/announcements/page.tsx

@@ -1,11 +1,11 @@
 import type { Metadata } from "next";
 import { cookies } from "next/headers";
 import Link from "next/link";
-import { Megaphone } from "lucide-react";
+import { Megaphone, Pin } from "lucide-react";
 import { fetchAnnouncementsPage, fetchOverview, type Announcement } from "@/lib/api";
 import { authCookieHeader } from "@/lib/cookies";
 import { getMeCached, getPublicSettingsCached } from "@/lib/serverData";
-import { isAdminOrAbove } from "@/lib/roles";
+import { hasPerm, PERMS } from "@/lib/roles";
 import { formatDate } from "@/lib/format";
 import Pagination from "@/components/Pagination";
 import {
@@ -57,7 +57,11 @@ function FeaturedAnnouncement({ a, urlStyle }: { a: Announcement; urlStyle: UrlS
         >
           置顶公告
         </span>
-        {a.pinned ? <span className="badge-pin">置顶</span> : null}
+        {a.pinned ? (
+          <span className="badge-pin" title="置顶" aria-label="置顶">
+            <Pin size={12} fill="currentColor" strokeWidth={2.2} aria-hidden />
+          </span>
+        ) : null}
         <span className={`j13-anno-tag is-${a.tag_color}`}>{a.tag}</span>
         <time className="meta text-[12px] tabular-nums ml-auto" dateTime={a.created_at}>
           {formatDate(a.created_at)}
@@ -87,7 +91,11 @@ function AnnouncementRow({ a, showDivider, urlStyle }: { a: Announcement; showDi
       style={showDivider ? { borderTop: "1px solid var(--line)" } : undefined}
     >
       <div className="flex items-center gap-2 flex-wrap">
-        {a.pinned ? <span className="badge-pin">置顶</span> : null}
+        {a.pinned ? (
+          <span className="badge-pin" title="置顶" aria-label="置顶">
+            <Pin size={12} fill="currentColor" strokeWidth={2.2} aria-hidden />
+          </span>
+        ) : null}
         <span className={`j13-anno-tag is-${a.tag_color}`}>{a.tag}</span>
         <time className="meta text-[12px] tabular-nums ml-auto" dateTime={a.created_at}>
           {formatDate(a.created_at)}
@@ -133,7 +141,7 @@ export default async function AnnouncementsListPage({ searchParams }: PageProps)
   const sidebarPages = overview?.sidebar_pages ?? [];
   const siteLead = settings.site_description?.trim() || undefined;
   const urlStyle = settings.url_style;
-  const canManagePages = !!me.user && isAdminOrAbove(me.user.role);
+  const canManagePages = !!me.user && hasPerm(me.user, PERMS.PAGES);
 
   // 首页置顶条目作头图；其余走列表行（置顶已在头图时不再重复）
   const featured = page === 1 ? announcements.find((a) => a.pinned) : undefined;