feat: 增强前端健壮性并添加刷新功能

- 添加刷新按钮和加载状态指示器
- 改进API请求错误处理和用户反馈
- 优化表单验证和登录逻辑
- 更新后端端口号并处理URL结尾斜杠
- 添加按钮悬停效果和移动端适配

index.html

@@ -32,7 +32,13 @@
 
         <!-- 下载区域 -->
         <div id="downloadSection" class="section">
-            <h2>可用App</h2>
+            <div style="display: flex; justify-content: space-between; align-items: center; margin-bottom: 15px;">
+                <h2>可用App</h2>
+                <div>
+                    <button id="refreshBtn" onclick="refreshAppList()">刷新</button>
+                    <span id="loadingIndicator" style="display: none; margin-left: 10px; font-size: 12px;">加载中...</span>
+                </div>
+            </div>
             <div id="appList"></div>
         </div>
     </div>