Add first-party PayPal payment adapter for @payloadcms/plugin-ecommerce

[pradelgorithm]

Feature request

Add a first-party PayPal payment adapter for @payloadcms/plugin-ecommerce.

Motivation

Payload's ecommerce plugin already exposes a payment adapter pattern, but Stripe appears to be the primary first-party/default payment provider today. For many real-world ecommerce and event-registration implementations, PayPal is still one of the most commonly requested processors, especially for organizations that already use PayPal Business, nonprofits/associations, international chapters, or markets where Stripe is not the client's preferred processor.

Right now, teams that need PayPal generally have to build a custom commerce/payment integration around Payload. That works, but it means every project re-solves the same standard payment concerns:

• Creating a PayPal order
• Capturing an approved PayPal order
• Mapping PayPal order/capture statuses to Payload transactions/orders
• Verifying payment status server-side before fulfillment
• Handling failed/canceled approvals
• Handling webhooks and idempotency
• Supporting sandbox/live configuration
• Supporting refunds later

It would be better for Payload's ecommerce ecosystem if common processors were supported through reusable adapters instead of requiring custom one-off integrations for standard checkout flows.

Proposed solution

Provide a first-party PayPal adapter for @payloadcms/plugin-ecommerce, similar in spirit to the Stripe adapter.

Possible developer experience:

import { ecommercePlugin } from '@payloadcms/plugin-ecommerce'
import { paypalAdapter } from '@payloadcms/plugin-ecommerce/payments/paypal'

export default buildConfig({
  plugins: [
    ecommercePlugin({
      payments: {
        adapter: paypalAdapter({
          clientID: process.env.PAYPAL_CLIENT_ID!,
          clientSecret: process.env.PAYPAL_CLIENT_SECRET!,
          environment: 'sandbox', // or 'live'
          intent: 'CAPTURE',
        }),
      },
    }),
  ],
})