A former top aide to Gov. Tina Kotek is officially leaving the office, months after going on leave in a shake-up tied to first lady Aimee Kotek Wilson. According to a resignation letter obtained in a public records request, Lindsey O’Brien, a former deputy chief of staff for Kotek, will serve her last day as a governor’s office employee on Oct. 11, more than six months after she last worked there.