feat: 添加管理员邮箱并替换CDN为本地bootstrap文件

添加ADMIN_EMAIL配置用于发送审核通知邮件
将所有页面引用的bootstrap CDN替换为本地/js/bootstrap.bundle.js

admin/system_info.php

@@ -174,7 +174,7 @@ $uploaded_files = get_uploaded_files_info();
     </div>
 
     <!-- Bootstrap JS Bundle with Popper -->
-    <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>
+    <script src="/js/bootstrap.bundle.js"></script>
 <script>
     document.getElementById('selectAll').addEventListener('change', function() {
         const checkboxes = document.querySelectorAll('input[name="delete_files[]"]');