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/TipHost.tsx

@@ -129,6 +129,10 @@ function shouldShowTip(host: Element, tip: string): boolean {
 /**
  * 全站悬停即显提示：监听 [data-tip]，替代浏览器原生 title 的延迟气泡。
  * 挂在 root layout 即可，业务侧写 data-tip="文案" 并保留 aria-label。
+ *
+ * 移动端策略：仅在 (hover: hover) and (pointer: fine) 设备上响应真实鼠标
+ * 指针与键盘焦点。触屏 tap 既派发合成鼠标事件又会抢占焦点，若照常弹出，
+ * 会出现「一点击就弹、只能点别处关闭」的体验，因此触屏一律不触发。
  */
 export default function TipHost() {
   const [tip, setTip] = useState<TipState>(null);
@@ -193,6 +197,15 @@ export default function TipHost() {
       }, delay);
     };
 
+    // 仅在具备真实悬停能力的设备（鼠标/触控板）上启用；纯触屏直接不参与
+    const hoverMq = window.matchMedia("(hover: hover) and (pointer: fine)");
+    let canHover = hoverMq.matches;
+    // 只在键盘导航期间允许聚焦气泡（:focus-visible 语义），点按产生的焦点不弹
+    let keyboardActive = false;
+    // 触摸后的短暂窗口，兜底忽略浏览器派发的合成鼠标事件
+    let lastTouchAt = 0;
+    const TOUCH_GUARD_MS = 500;
+
     const onOver = (e: Event) => {
       const t = e.target;
       if (!(t instanceof Element)) return;
@@ -204,8 +217,19 @@ export default function TipHost() {
       tryShow(host);
     };
 
+    const onPointerOver = (e: PointerEvent) => {
+      if (!canHover || e.pointerType !== "mouse") return;
+      if (Date.now() - lastTouchAt < TOUCH_GUARD_MS) return;
+      onOver(e);
+    };
+
+    const onFocusIn = (e: FocusEvent) => {
+      if (!canHover || !keyboardActive) return;
+      onOver(e);
+    };
+
     const onOut = (e: Event) => {
-      if (!(e instanceof MouseEvent) && !(e instanceof FocusEvent)) return;
+      if (!(e instanceof PointerEvent) && !(e instanceof FocusEvent)) return;
       const related = "relatedTarget" in e ? e.relatedTarget : null;
       if (
         related instanceof Node &&
@@ -217,25 +241,52 @@ export default function TipHost() {
       hide();
     };
 
+    const onKeyDown = () => {
+      keyboardActive = true;
+    };
+
+    const onPointerDown = (e: PointerEvent) => {
+      if (e.pointerType !== "keyboard") keyboardActive = false;
+    };
+
+    const onTouchStart = () => {
+      lastTouchAt = Date.now();
+      keyboardActive = false;
+      hide();
+    };
+
+    const onHoverMqChange = (e: MediaQueryListEvent) => {
+      canHover = e.matches;
+      if (!canHover) hide();
+    };
+
     const onScrollOrResize = () => {
       if (!activeEl.current) return;
       tryShow(activeEl.current);
     };
 
-    // mouseover 冒泡，便于 closest；立即显示，无延时
-    document.addEventListener("mouseover", onOver);
-    document.addEventListener("mouseout", onOut);
-    document.addEventListener("focusin", onOver);
+    // pointerover 冒泡，便于 closest；仅响应真实鼠标指针，触屏/手写笔不弹
+    document.addEventListener("pointerover", onPointerOver);
+    document.addEventListener("pointerout", onOut);
+    document.addEventListener("focusin", onFocusIn);
     document.addEventListener("focusout", onOut);
+    document.addEventListener("keydown", onKeyDown, true);
+    document.addEventListener("pointerdown", onPointerDown, true);
+    document.addEventListener("touchstart", onTouchStart, true);
+    hoverMq.addEventListener("change", onHoverMqChange);
     window.addEventListener("scroll", onScrollOrResize, true);
     window.addEventListener("resize", onScrollOrResize);
 
     return () => {
       clearPending();
-      document.removeEventListener("mouseover", onOver);
-      document.removeEventListener("mouseout", onOut);
-      document.removeEventListener("focusin", onOver);
+      document.removeEventListener("pointerover", onPointerOver);
+      document.removeEventListener("pointerout", onOut);
+      document.removeEventListener("focusin", onFocusIn);
       document.removeEventListener("focusout", onOut);
+      document.removeEventListener("keydown", onKeyDown, true);
+      document.removeEventListener("pointerdown", onPointerDown, true);
+      document.removeEventListener("touchstart", onTouchStart, true);
+      hoverMq.removeEventListener("change", onHoverMqChange);
       window.removeEventListener("scroll", onScrollOrResize, true);
       window.removeEventListener("resize", onScrollOrResize);
     };