优化内容库分页

- 默认每页20条
- 列表上部也添加分页控件，方便翻页

static/css/library.css

@@ -263,6 +263,19 @@
     color: #4caf50;
 }
 
+/* 上部分页 */
+.pagination-top {
+    display: flex;
+    align-items: center;
+    gap: 10px;
+    margin-left: auto;
+}
+
+.pagination-top span {
+    font-size: 14px;
+    color: #666;
+}
+
 .article-summary {
     font-size: 14px;
     color: #666;

static/js/library.js

@@ -4,7 +4,7 @@ const API_BASE = '';
 // 状态
 let articles = [];
 let currentPage = 1;
-let pageSize = 100;
+let pageSize = 20;  // 默认每页20条
 let totalCount = 0;
 let selectedIds = new Set();
 let currentArticleId = null;
@@ -157,8 +157,14 @@ function displayArticles() {
 // 更新分页
 function updatePagination() {
     const totalPages = Math.ceil(totalCount / pageSize);
-    document.getElementById('page-info').textContent = `第 ${currentPage} / ${totalPages || 1} 页`;
     
+    // 更新上部分页
+    document.getElementById('page-info-top').textContent = `第 ${currentPage} / ${totalPages || 1} 页`;
+    document.getElementById('prev-btn-top').disabled = currentPage <= 1;
+    document.getElementById('next-btn-top').disabled = currentPage >= totalPages;
+    
+    // 更新下部分页
+    document.getElementById('page-info').textContent = `第 ${currentPage} / ${totalPages || 1} 页`;
     document.getElementById('prev-btn').disabled = currentPage <= 1;
     document.getElementById('next-btn').disabled = currentPage >= totalPages;
 }