* refactor(client): remove double caching of models via recoil to rely exclusively on react-query
* chore(useConversation): add modelsQuery.data dep to callback
* refactor: move endpoint services to own directory
* refactor: make endpointconfig handling more concise, separate logic, and cache result for subsequent serving
* refactor: ModelController gets same treatment as EndpointController, draft OverrideController
* wip: flesh out override controller more to return real value
* refactor: client/api changes in anticipation of override