HALIFAX—Nova Scotia’s Progressive Conservatives surged to an upset election win Tuesday over the governing Liberals after capitalizing on their main opponent’s early stumbles and promising a big−spending fix to the troubled health system. As the victory celebrations unfolded at Houston’s headquarters at a sports facility near New Glasgow, N.S., party stalwarts spoke of a huge turnaround from the beginning of the race. “We’re ecstatic,” Tara Miller said with a laugh. Miller, a co−chair with the Tory campaign, said the party was able to pull itself up in the polls after being down nearly 30 points earlier this summer. “To have closed that gap during the pandemic election is historic,” she said. Houston’s party has become the first to unseat a sitting government in Canada since the start of the COVID−19 pandemic. Other elections that have taken place during the course of the health crisis — in Newfoundland and Labrador, New …