refactor(member-card): 更新扩展ID并移除旧信息文件

- 将扩展ID从 "six-shop-member-card" 更改为 "member_card"
- 删除旧的 info.php 配置文件
- 统一扩展标识符命名规范
- 移除冗余的配置声明
- 简化扩展元数据结构
- 提高代码一致性与可维护性

composer.json

@@ -24,7 +24,7 @@
   },
   "extra": {
     "sixshop": {
-      "id": "six-shop-member-card",
+      "id": "member_card",
       "class": "SixShop\\MemberCard\\Extension"    }
   },
   "minimum-stability": "dev",

info.php

@@ -1,7 +0,0 @@
-<?php
-declare(strict_types=1);
-
-return [
-    'id' => 'six-shop-member-card',
-    'name' => '会员卡包',
-];