新增 Stripe 支付入口，支持任意金额充值

## 参考文档

1. https://docs.stripe.com/js
2. https://vercel.com/guides/getting-started-with-nextjs-typescript-stripe
3. https://medium.com/@gragson.john/stripe-checkout-and-webhook-in-a-next-js-15-2025-925d7529855e

## 参考代码

1. https://github.com/vercel/nextjs-subscription-payments
2. https://github.com/nextjs/saas-starter