修复收藏/聊天记录检索的请求竞态、下载页按钮占一半宽度、两个类名零CSS覆盖

- Favorites/History 组件的 load() 原来没有过期响应保护：切换类型/输入搜索词都会触发新请求，
  但如果一个更早发出的、范围更宽的请求（比如"全部"）比后发的窄范围搜索请求更晚返回，会无条件
  覆盖掉已经正确显示的搜索结果——实测复现过"搜索框显示查询词，列表却是全量未过滤结果"。改成
  每次调用 load() 时认领一个自增计数器，响应到达时如果计数器已经被更新的调用推进过，直接丢弃
  这个过期响应。History组件（按topic/tab/query切换）是同一个模式，一并修复。
- `.library-download-actions`（下载页loading/done两态的按钮容器）是2列等宽grid，但两个状态
  永远只渲染1个按钮——按钮固定占左侧50%宽度，右侧约一半容器宽度是死空白。改成单列。
- `.library-empty-hint`（收藏/聊天记录/下载页的加载中提示文字）和`.library-load-more`
  （"加载更多"按钮）在base.css里完全没有对应规则，退化成浏览器默认段落间距/按钮外观——
  补了基础样式，跟第八轮修复的.library-link-text/.library-record-header是同一类遗漏。

均已重新构建并实测验证（下载按钮宽度、空状态文字样式、加载更多按钮样式均用真实DOM测量确认；
请求竞态修复通过真实收藏页搜索/清空往返验证无回归，竞态本身的精确时序难以在测试环境里稳定
复现，但修复采用的是标准、成熟的自增计数器丢弃过期响应模式）。

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

css/base.css

@@ -10902,6 +10902,30 @@ div.toast.show {
   flex: 1 1 auto;
 }
 
+/* Favorites/History/DownloadPage's loading/error placeholder text and Favorites/History's "加载
+   更多" pagination button -- both had zero rules anywhere in this file, falling back to a bare
+   <p>'s default margins and a plain <button>'s default outline respectively. */
+.library-empty-hint {
+  padding: 1.5rem 1rem;
+  color: #9299a2;
+  font-size: 0.85rem;
+  text-align: center;
+}
+
+.library-load-more {
+  display: block;
+  width: min(100%, 52rem);
+  margin: 0 auto;
+  padding: 0.8rem;
+  border: 1px solid #eceef1;
+  border-radius: 0.4rem;
+  box-shadow: none;
+  color: #567;
+  background: #fff;
+  font-size: 0.85rem;
+  text-transform: none;
+}
+
 .library-favorite-item {
   display: flex;
   gap: 0.7rem;
@@ -11482,9 +11506,12 @@ div.toast.show {
   color: #9299a2;
 }
 
+/* DownloadPage's loading ("取消") and done ("用其他应用打开") states each render exactly one button
+   here -- never two side by side -- so the 2nd 1fr column sat permanently empty, pinning the
+   button to the left half with the right half dead space. */
 .library-download-actions {
   display: grid;
-  grid-template-columns: 1fr 1fr;
+  grid-template-columns: 1fr;
   gap: 0.8rem;
 }
 

src/views/content-library-view.jsx

@@ -220,8 +220,16 @@ function Favorites({view, tinode, onToast}) {
   const [hasMore, setHasMore] = React.useState(false);
   const [fileUrls, setFileUrls] = React.useState({});
   const [sourceNames, setSourceNames] = React.useState({});
+  // An in-flight request isn't guaranteed to resolve before a newer one its own type/query change
+  // triggered -- without this, a slow full-list request landing after a fast, narrower search
+  // response overwrites the correct filtered results with the stale unfiltered ones (confirmed
+  // live: search box showing a query, list showing all items). Each load() call claims the counter
+  // for itself; a response only applies if nothing newer has been requested since.
+  const requestIdRef = React.useRef(0);
   const load = React.useCallback((append) => {
+    const requestId = ++requestIdRef.current;
     getFavorites({type, query, cursor: append ? cursor : ''}).then(data => {
+      if (requestIdRef.current !== requestId) return;
       setItems(prev => {
         const list = append ? (prev || []).concat(data.items || []) : (data.items || []);
         if (!query) writeCachedData('favorites:' + type, list);
@@ -523,12 +531,18 @@ function History({view, hashParams, myUserId, onToast}) {
   const [hasMore, setHasMore] = React.useState(false);
   const [mediaUrls, setMediaUrls] = React.useState({});
   const [senderNames, setSenderNames] = React.useState({});
+  // Same stale-response guard as Favorites' load() above and for the same reason -- a slower
+  // request for a since-abandoned topic/tab/query can still resolve after a newer one and
+  // overwrite its correct results.
+  const requestIdRef = React.useRef(0);
   const load = React.useCallback((append) => {
     if (!topic) return;
+    const requestId = ++requestIdRef.current;
     const type = HISTORY_TYPE[view];
     const call = view === 'history-search' ? searchTopicMessages(topic, {query, type, cursor: append ? cursor : ''}) :
       getTopicMedia(topic, type, append ? cursor : '');
     call.then(data => {
+      if (requestIdRef.current !== requestId) return;
       setItems(prev => {
         const list = append ? (prev || []).concat(data.items || []) : (data.items || []);
         if (!query && cacheKey) writeCachedData(cacheKey, list);

umd/index.dev.js

@@ -9263,12 +9263,15 @@ function Favorites({
   const [hasMore, setHasMore] = react__WEBPACK_IMPORTED_MODULE_0___default().useState(false);
   const [fileUrls, setFileUrls] = react__WEBPACK_IMPORTED_MODULE_0___default().useState({});
   const [sourceNames, setSourceNames] = react__WEBPACK_IMPORTED_MODULE_0___default().useState({});
+  const requestIdRef = react__WEBPACK_IMPORTED_MODULE_0___default().useRef(0);
   const load = react__WEBPACK_IMPORTED_MODULE_0___default().useCallback(append => {
+    const requestId = ++requestIdRef.current;
     (0,_lib_im_api_js__WEBPACK_IMPORTED_MODULE_5__.getFavorites)({
       type,
       query,
       cursor: append ? cursor : ''
     }).then(data => {
+      if (requestIdRef.current !== requestId) return;
       setItems(prev => {
         const list = append ? (prev || []).concat(data.items || []) : data.items || [];
         if (!query) (0,_lib_use_cached_data_js__WEBPACK_IMPORTED_MODULE_6__.writeCachedData)('favorites:' + type, list);
@@ -9762,8 +9765,10 @@ function History({
   const [hasMore, setHasMore] = react__WEBPACK_IMPORTED_MODULE_0___default().useState(false);
   const [mediaUrls, setMediaUrls] = react__WEBPACK_IMPORTED_MODULE_0___default().useState({});
   const [senderNames, setSenderNames] = react__WEBPACK_IMPORTED_MODULE_0___default().useState({});
+  const requestIdRef = react__WEBPACK_IMPORTED_MODULE_0___default().useRef(0);
   const load = react__WEBPACK_IMPORTED_MODULE_0___default().useCallback(append => {
     if (!topic) return;
+    const requestId = ++requestIdRef.current;
     const type = HISTORY_TYPE[view];
     const call = view === 'history-search' ? (0,_lib_im_api_js__WEBPACK_IMPORTED_MODULE_5__.searchTopicMessages)(topic, {
       query,
@@ -9771,6 +9776,7 @@ function History({
       cursor: append ? cursor : ''
     }) : (0,_lib_im_api_js__WEBPACK_IMPORTED_MODULE_5__.getTopicMedia)(topic, type, append ? cursor : '');
     call.then(data => {
+      if (requestIdRef.current !== requestId) return;
       setItems(prev => {
         const list = append ? (prev || []).concat(data.items || []) : data.items || [];
         if (!query && cacheKey) (0,_lib_use_cached_data_js__WEBPACK_IMPORTED_MODULE_6__.writeCachedData)(cacheKey, list);