Model
The name of a registered embedding service.
The counterpart of RoleResolution.Options, carrying a name rather than an options object because there is nothing to tune: an embedding model takes text and returns a vector, and the one parameter that would vary - the width - is the model's to state, not the caller's to ask for. See ConfigurableModelProviderProperties.embeddingRoles for why the configuration shape is flatter than roles for the same reason.