CHENNAI, India — Now that artificial intelligence has mastered almost everything we do online, it needs help learning how we physically move around in the real world. A growing global army of trainers is helping it escape our computers and enter our living rooms, offices and factories by teaching it how we move. In an industrial town in southern India, Naveen Kumar, 28, stands at his desk and starts his job for the day: folding hand towels hundreds of times, as precisely as possible. He doesn’t ...