PaymentHost

Platform handle a PaymentGateway needs to launch its SDK/UI. Deliberately opaque in commonMain — it carries no platform types, so the contract stays multiplatform. On Android the concrete host (see AndroidPaymentHost in androidMain) owns the ComponentActivity + ActivityResult plumbing and bridges the SDK's callback back into the suspending PaymentGateway.pay call.

This indirection is the heart of the architecture: it lets Compose-era, coroutine-based feature code drive Activity-callback-era gateway SDKs without leaking Activity references upward.

Inheritors