Matthew Tessier fixes broken schools. Chula Vista's Harborside Elementary was in pieces when he arrived as its principal two years ago. The school next to a mobile-home park in an impoverished neighborhood had failed to reach federal benchmarks for so long that the menu of remedies included shutting it down. But Tessier, 35, is a turnaround specialist. Before he arrived at Harborside, Tessier had done what only a few dozen principals in the county had ever done: He led a school — Loma Verde Elementary — safely out of federal sanctions with two consecutive years of dramatically improved test scores....