Generate AI videos using BytePlus Seedance API (International). Use when the user wants to: (1) generate videos from text prompts, (2) generate videos from images (first frame, first+last frame, reference images), or (3) query/manage video generation tasks. Supports Seedance 1.5 Pro (with audio & draft mode), 1.0 Pro, 1.0 Pro Fast, and 1.0 Lite models.