Restore hidden teleop episodes and MEgo ego samples

TEMP: hide teleop episodes (keep 4 Faber U tasks) and MEgo ego samples

egoSample: add Robot Ego · Multi-Sensor Capture category (planned) with Faber U shelf-restocking episode

egoSample: add Jizhi Stereo photo keychain crafting (Creative Workshops)

egoSample: add inline '← all datasets' link in the sidebar header

egoSample: unified scenario-grouped viewer (5 MEgo 5-cam tasks + 6 PICO demos)

Card hover affordance: dim thumbnail + centered play triangle on episode/demo cards

egoSample: 6-episode gallery + per-demo ego viewers (hand/head 3D, download links)