feat: 支持官方支付宝与易支付支付宝同时展示

- PaymentType 改为 string 类型，支持复合 key（如 alipay_direct）
- 官方支付宝注册为 alipay_direct，易支付保持 alipay/wxpay
- 前端按 PAYMENT_TYPE_META 展示标签区分（官方直连/易支付）
- 管理后台显示统一改为 getPaymentTypeLabel 通用映射
- 修复 admin/OrderTable 中 wechat 拼写错误

src/lib/alipay/provider.ts

@@ -14,11 +14,11 @@ import { getEnv } from '@/lib/config';
 import type { AlipayTradeQueryResponse, AlipayTradeRefundResponse, AlipayTradeCloseResponse } from './types';
 
 export class AlipayProvider implements PaymentProvider {
-  readonly name = 'alipay';
+  readonly name = 'alipay-direct';
   readonly providerKey = 'alipay';
-  readonly supportedTypes: PaymentType[] = ['alipay'];
+  readonly supportedTypes: PaymentType[] = ['alipay_direct'];
   readonly defaultLimits = {
-    alipay: { singleMax: 1000, dailyMax: 10000 },
+    alipay_direct: { singleMax: 1000, dailyMax: 10000 },
   };
 
   async createPayment(request: CreatePaymentRequest): Promise<CreatePaymentResponse> {