feat: 添加调试日志并改进数据库处理逻辑

- 在多个文件中添加调试日志记录功能
- 将数据库连接统一迁移到db_connect.php
- 改进预约时间冲突检测逻辑
- 优化VIP客户数据处理
- 增强套餐查询的健壮性
- 更新预约状态处理流程

vip.php

@@ -414,13 +414,19 @@ try {
                             <option value="">请选择套餐</option>
                             <?php
                             // 查询所有可用的洗车套餐
-                            $package_result = $conn->query("SELECT id, package_name, price FROM packages ORDER BY price ASC");
-                            if ($package_result && $package_result->num_rows > 0) {
-                                while ($package = $package_result->fetch_assoc()) {
+                            // #region agent log
+                            $log_data = json_encode(['location' => 'vip.php:417', 'message' => 'Loading packages', 'data' => ['using_pdo' => isset($pdo), 'using_conn' => isset($conn)], 'timestamp' => time() * 1000, 'sessionId' => 'debug-session', 'runId' => 'run1', 'hypothesisId' => 'B']);
+                            file_put_contents('.cursor/debug.log', $log_data . "\n", FILE_APPEND);
+                            // #endregion
+                            try {
+                                $stmt = $pdo->query("SELECT id, package_name, price FROM packages WHERE is_active = 1 ORDER BY price ASC");
+                                $packages = $stmt->fetchAll();
+                                foreach ($packages as $package) {
                                     echo "<option value='{$package['id']}'>{$package['package_name']} - ¥{$package['price']}</option>";
                                 }
+                            } catch (Exception $e) {
+                                echo "<option value=''>加载套餐失败</option>";
                             }
-                            $package_result->free_result();
                             ?>
                         </select>
                     </div>