Read the project mood board (the agreed look, as kept frames).

The kept frames every new character render is made in. Costs no credits. A project that has agreed no look yet returns an empty board rather than a 404, because "no look agreed yet" is a normal state. It also answers with candidates — frames this project has RENDERED and not kept, which is where the urls keepProjectMoodBoardFrame needs come from — and renders, the recent batches and where each one got to, so a poll after renderProjectMoodBoardFrames terminates instead of waiting forever on a batch that failed.