- Add new ModelversePreviewVideo node for downloading and previewing generated videos
- Change all Vidu video generation nodes (extend, i2v, ref2v, startend2v, t2v) to return video URL and task ID instead of downloaded video objects
- Change all Wan AI video generation nodes (i2v, t2v) to return video URL and task ID instead of downloaded video objects
- Remove duplicate VideoFromFile import fallback logic from all video generation modules
- Simplify video handling by delegating download responsibility to preview node
- Improve separation of concerns between generation and preview workflows