ANN ARBOR, Mich. — Maybe some people have doubts. Maybe some wonder if last season’s Big Ten championship was an outlier, or if NFL ambitions still linger. Jim Harbaugh clearly has heard it all, and with spring football underway, well, he figured it was a swell time to quell. “The state of Michigan football is scary good right now,” Harbaugh said, his inflection rising, his smile beaming. It was unclear if he was predicting championships, projecting personal fulfillment, or simply excited about the talent he sees in practice. But for 30 minutes Tuesday, he rattled off the reasons he enjoys his…