The members of Chai can’t stop smiling. On a Wednesday night in early September, the Japanese quartet is making its live New York debut, and their presence is sheer glee. Mana, Kana, Yuki, and Yuna are dressed in matching bubblegum pink jumpsuits with a wide-leg cut inspired by a character from the Hayao Miyazaki anime film Castle in the Sky. They trade delightfully simple synchronized dance moves