The mayor of Northern California’s largest city has sized up Gov. Gavin Newsom more and more in the past year — building his statewide profile as a centrist foil for other Democrats in the process. But when, if ever, will the state be ready for San Jose Mayor Matt Mahan to become governor? Articulate, young and always camera-ready, Mahan is already building name recognition up and down the state. He publicly ruffled Newsom’s feathers on crime an…