In the years since Brad Stevens moved upstairs to become president of the Celtics, Boston has been a team to watch every offseason. In four of the last five years the franchise has been aggressive to varying degrees in the trade market and free agency, with the lone exception coming after the C’s won the 2024 title. It’s proven that Stevens isn’t fond of sitting on his hands and will not hesitate to take big swings if he thinks it’ll improve the roster—and nobody is safe in his pursuit of success. Based on that precedent, Boston figured to be a team to watch this upcoming offseason. After Stevens spoke to the media on Wednesday for the first time since his team blew a 3–1 first-round series lead to the 76ers, that’s all but confirmed. In his annual end-of-season press conference, Stevens sat and took questions from reporters for nearly 30 minutes on how this Celtics season went.…