feat: 添加基金邮件定时发送功能并优化邮件内容格式

- 新增宝塔面板定时任务脚本 cron_send_email.php
- 添加手动发送邮件按钮到管理界面
- 使用PHPMailer替代原始SMTP实现
- 优化邮件内容格式，按涨跌幅排序基金数据
- 增加邮件发送时间窗口判断逻辑
- 更新项目文档说明定时任务配置

send_fund_email.php

@@ -0,0 +1,44 @@
+<?php
+/**
+ * 单独处理发送基金状态邮件的请求
+ */
+
+// 设置响应头
+header('Content-Type: application/json; charset=utf-8');
+header('Access-Control-Allow-Origin: *');
+header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
+header('Access-Control-Allow-Headers: Content-Type, charset');
+
+// 处理OPTIONS请求
+if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
+    exit(0);
+}
+
+// 验证管理员权限
+session_start();
+// 调试模式：允许通过debug参数绕过权限验证
+$isDebugMode = (isset($_GET['debug']) && $_GET['debug'] === 'true') || (isset($_POST['debug']) && $_POST['debug'] === 'true');
+if (!$isDebugMode && (!isset($_SESSION['admin_logged_in']) || $_SESSION['admin_logged_in'] !== true)) {
+    http_response_code(403);
+    echo json_encode(['success' => false, 'error' => '权限不足']);
+    exit;
+}
+
+// 引入FundMonitorAPI
+require_once 'api.php';
+$api = new FundMonitorAPI();
+
+try {
+    // 调用发送基金状态邮件方法，传入true参数强制发送
+    $result = $api->sendFundStatusEmail(true);
+    if ($result) {
+        echo json_encode(['success' => true, 'message' => '邮件发送成功']);
+    } else {
+        echo json_encode(['success' => false, 'error' => '邮件发送失败，请查看日志']);
+    }
+} catch (Exception $e) {
+    http_response_code(500);
+    echo json_encode(['success' => false, 'error' => $e->getMessage()]);
+}
+
+exit(0);