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/__tests__/lib/alipay/provider.test.ts

@@ -37,21 +37,21 @@ describe('AlipayProvider', () => {
   });
 
   describe('metadata', () => {
-    it('should have name "alipay"', () => {
-      expect(provider.name).toBe('alipay');
+    it('should have name "alipay-direct"', () => {
+      expect(provider.name).toBe('alipay-direct');
     });
 
     it('should have providerKey "alipay"', () => {
       expect(provider.providerKey).toBe('alipay');
     });
 
-    it('should support "alipay" payment type', () => {
-      expect(provider.supportedTypes).toEqual(['alipay']);
+    it('should support "alipay_direct" payment type', () => {
+      expect(provider.supportedTypes).toEqual(['alipay_direct']);
     });
 
     it('should have default limits', () => {
       expect(provider.defaultLimits).toEqual({
-        alipay: { singleMax: 1000, dailyMax: 10000 },
+        alipay_direct: { singleMax: 1000, dailyMax: 10000 },
       });
     });
   });