async init() {
    this.#providerSetupAndCheck();
    return this;
  }
Finds or assumes the model preference value to use for API calls.
If multi-model loading is supported, we use their agent model selection of the workspace
If not supported, we attempt to fallback to the system provider value for the LLM preference
and if that fails - we assume a reasonable base model to exist.
@returns {string|null} the model preference value to use in API calls