Boston’s biggest signing on the first day of free agency was a rugged left wing. The Bruins gave Tanner Jeannot a five-year, $17 million deal ($3.4 million AAV) to add some thump to their bottom six. The 6-foot-2, 220-pounder plays a physical game and has flashed a high ceiling, but the 28-year-old hasn’t reached it over the past three seasons.