Fix thumbnail URL (sddefault)

YouTube thumbnail link for trajectory video

Test YouTube iframe embed

Embed trajectory video + YouTube link

drop the combined sheet; rename to so101_coffee_subtask and fix the red-cup wording

viz: drop the 12 single-step figures, superseded by the 3-step rows

card: show all 12 steps as four 3-step rows

card: replace step 1/2/3 embeds with one combined row image

Add dataset card with 24-block episode-range index