The hottest new gig-economy job in Los Angeles is performing at home to help artificial intelligence understand how humans move. Hundreds of people from Santa Monica to Los Feliz are strapping cameras on their heads and hands as they do chores at home so bots can watch how they make coffee, scrub toilets, water plants and wash dishes. At a corner table at Urth Caffe downtown, a woman is sitting next to a big black bag. A constant flow of visitors stops by. She slips each a package and instructions, and they move on. “People think I am selling” drugs, she says. She’s actually a manager for a San Francisco-based firm called Instawork that connects companies and blue-collar workers, and she’s handing out headbands with phone mounts, a simple piece of equipment that lets people record their every move — movements that will be turned into data to train robots how to act. She hands Salvador Arciga a headmount and tells him to go home and do the dishes and clean his kitchen. He has …