v1.20.0

What's Changed

Async polling for media generation

Image, music, and video generation now use async initiate+poll patterns instead of synchronous blocking calls. This avoids timeout issues on long-running generations and shows a spinner with status updates while waiting.

• Image: image_create_image_async + image_get_image_async (polls every 3s)
• Music: music_create_async + music_get_async (polls every 5s)
• Video: create_video + wait_for_video (polls every 10s)