1. Add "videoTrim" to source type check in orderedClips so VideoTrim
node outputs are recognized and thumbnails are extracted
2. Generate thumbnails at source video's native aspect ratio instead
of fixed 160x120 (4:3) to prevent distortion
3. Change thumbnail display from object-cover to object-contain to
prevent cropping/distortion when the node is resized
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>