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/components/AcceptedAnswerCard.tsx

@@ -1,7 +1,7 @@
 import Link from "next/link";
 import { CheckCircle2, CircleHelp, Coins } from "lucide-react";
 import type { AcceptedAnswer } from "@/lib/api";
-import { userPath } from "@/lib/urlStyle";
+import { userPath, commentAnchor } from "@/lib/urlStyle";
 import { getPublicSettingsCached } from "@/lib/serverData";
 import Avatar from "@/components/Avatar";
 import MarkdownBody from "@/components/MarkdownBody";
@@ -74,7 +74,7 @@ export default async function AcceptedAnswerCard({
                   <>
                     <span aria-hidden>·</span>
                     <a
-                      href={`#comment-${answer.id}`}
+                      href={commentAnchor(answer.floor, answer.is_root, answer.id)}
                       className="hover:underline"
                       style={{ color: "var(--accent)" }}
                     >
@@ -95,7 +95,7 @@ export default async function AcceptedAnswerCard({
                 <>
                   <span aria-hidden>·</span>
                   <a
-                    href={`#comment-${answer.id}`}
+                    href={commentAnchor(answer.floor, answer.is_root, answer.id)}
                     className="hover:underline"
                     style={{ color: "var(--accent)" }}
                   >