The underdog Hampden Academy team pushed powerhouse Cheverus and star pitcher Addison DeRoche to the brink Saturday in Auburn, but the Stags scratched across the go-ahead run in the seventh inning to claim a 3-2 victory and the Class A softball state championship. Cheverus, led by DeRoche, who was Maine’s Gatorade Softball Player of the Year and is already a Florida State University commit as a junior, struck first in the top of the second innin…