ApiClientFactory

Create effectful methods to perform the endpoint operation.

The factory takes an endpoint with correct type signature, and returns a function that can call the endpoint.

The resulting error channel is whatever the endpoint declares as the client error channel, eg. the type E of ApiError[E], which is what is reported in RequestFailure[E].

The other options - AuthenticationFailure, ServerFailure - are converted to defects to be handled at another level.

This way the client can deal only with what it can actually do something about.