config: set default locale to English and update CREEM production URLs

- Change default locale from zh to en for international audience
- Update .env.example with production CREEM API URL
- Set SUCCESS_URL to meeyao.com/en/store

.env.example

@@ -120,7 +120,10 @@ ERYAO_APPLE_IAP__SERVER_NOTIFICATIONS_URL=
 ############
 # CREEM Payment 配置
 ############
+# 生产环境: https://api.creem.io
+# 测试环境: https://test-api.creem.io
 ERYAO_CREEM__API_KEY=
 ERYAO_CREEM__WEBHOOK_SECRET=
-ERYAO_CREEM__BASE_URL=https://test-api.creem.io
-ERYAO_CREEM__SUCCESS_URL=https://yourdomain.com/store?payment=success
+ERYAO_CREEM__BASE_URL=https://api.creem.io
+# 支付成功后跳转链接，需包含语言前缀
+ERYAO_CREEM__SUCCESS_URL=https://meeyao.com/en/store?payment=success