Run a saved recipe or workflow

Compiles the recipe on the server with your inputs and starts a run (one task per piece; a workflow runs its steps in order, each step using the earlier steps' results). Inputs you leave out use the material saved with the recipe. Media inputs take popnow://g/<job>/<n> (a result), popnow://f/<file> (an upload), popnow://a/<asset> (an API asset) or an https URL, or a list of them; the prompt input of a recipe (and text inputs of a workflow) take plain text. The run is priced at current list prices first. With maxCredits, a run that would cost more is not started (409); without it, the run starts at the quoted price. The run never spends more than that amount. Keys with a model list or a spending limit can't run recipes (403). Replaying the same Idempotency-Key returns the same run.