Hard-throwing SoftBank Hawks ace Kodai Senga said Saturday that he will exercise his rights to file for free agency in order to play in MLB next season. The 29-year-old right-hander earned the win in Game 3 of the Pacific League’s Climax Series final stage on Friday before the Hawks were eliminated from the postseason on Saturday. “I’m absolutely going to file for free agency,” Senga said. “I’ve been saying I’m going to do it for the past six years, so this represents nothing new for me.” Senga, who turned pro in 2011 with the Hawks on a non-roster developmental contract, has a career record o…