refactor: 简化成功消息并调整预约时长选项

移除预约成功消息中的冗余信息，并调整时长选择按钮，增加6小时和8小时选项，移除3小时选项

index.php

@@ -103,7 +103,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         $stmt->execute([$customer_name, $phone, $car_model, $car_number, $package_id, $custom_services,
                        $start_time, $end_time, $duration, $total_price, $notes, $member_type, $source]);
 
-        $success_message = "预约提交成功！我们会尽快联系您确认。";
+        $success_message = "预约提交成功！";
         
     } catch (Exception $e) {
         $message = $e->getMessage();
@@ -512,8 +512,9 @@ $packages_json = json_encode(array_map(function($package) {
                         <button type="button" class="duration-btn" onclick="selectDuration(60)">1小时</button>
                         <button type="button" class="duration-btn" onclick="selectDuration(90)">1.5小时</button>
                         <button type="button" class="duration-btn" onclick="selectDuration(120)">2小时</button>
-                        <button type="button" class="duration-btn" onclick="selectDuration(180)">3小时</button>
                         <button type="button" class="duration-btn" onclick="selectDuration(240)">4小时</button>
+                        <button type="button" class="duration-btn" onclick="selectDuration(360)">6小时</button>
+                        <button type="button" class="duration-btn" onclick="selectDuration(480)">8小时</button>
                         <button type="button" class="duration-btn" onclick="selectDuration(720)">12小时</button>
                         <input type="number" id="customDuration" min="30" step="30" value="60" style="width: 80px; margin-left: 10px;">
                         <button type="button" class="btn btn-sm" onclick="applyCustomDuration()">确定</button>