feat(subscription): support balance purchases

Refs #3071.

web/default/src/i18n/locales/zh.json

@@ -2035,6 +2035,7 @@
     "Inspect requests, errors, and billing details": "查看请求、错误和计费详情",
     "Inspect user prompts": "检查用户提示",
     "Instance": "实例",
+    "Insufficient balance": "余额不足",
     "Integrations": "集成",
     "Inter-group overrides": "分组间覆盖",
     "Inter-group ratio overrides": "分组间比例覆盖",
@@ -2852,6 +2853,7 @@
     "Path:": "路径：",
     "Pay": "支付",
     "Pay-as-you-go with real-time usage monitoring": "按量付费，实时监控使用情况",
+    "Pay with Balance": "使用余额支付",
     "Payment": "支付",
     "Payment aggregator mode — onboard with your own registered company (offshore entity). Built for Enterprise.": "支付聚合模式：使用你自己的注册公司（离岸实体）入驻。面向企业场景构建。",
     "Payment Channel": "支付渠道",
@@ -3763,6 +3765,7 @@
     "Subscription First": "优先订阅",
     "Subscription Management": "订阅管理",
     "Subscription Only": "仅用订阅",
+    "Subscription purchased successfully": "订阅购买成功",
     "Subscription plan creation and changes are locked until the administrator confirms compliance terms in Payment Gateway settings.": "管理员在支付网关设置中确认合规条款之前，订阅套餐的创建和修改会被锁定。",
     "Subscription Plans": "订阅套餐",
     "Subscription plans do NOT use the bound Product — each plan has its own dedicated Pancake product, set in the Subscriptions admin (or auto-minted via the \"+ Create\" button there).": "订阅套餐不会使用已绑定的产品。每个套餐都有独立的 Pancake 产品，可在订阅管理中设置，或通过其中的“+ 创建”按钮自动生成。",