Integrate Stripe, PayPal, and payment processors. Handles checkout flows, subscriptions, webhooks, and PCI compliance. Use PROACTIVELY when implementing payments, billing, or subscription features.

集成 Stripe、PayPal 和支付处理器，处理结账流程、订阅、Webhook 和 PCI 合规。在实现支付、计费或订阅功能时主动使用。