Update pipeline

Update a pipeline: rename it, change its description, or replace its node graph. For a graph change, read the current one with get_pipeline includeGraph and send the whole graph back, nodes and edges together, every edge naming the two nodes it joins and a port on each, e.g. {"source":"music","sourceHandle":"audio","target":"sequence","targetHandle":"shots"}. A graph with error-level issues is refused with every issue listed, and nothing is saved; settings you change are checked against get_node_type and the live model catalog the same way create_pipeline checks them. To add music, narration or captions to a video a run already made, pass its url from get_run outputs to assemble_video or edit_asset instead: a changed pipeline renders every node again when it runs, the video included, and charges for it.