There were many reasons for Brandie Wilkerson to smile that thousand-watt smile of hers on Saturday night. Just take your pick for which one might have lit her up the brightest: She and Sophie Bukovec had just beaten Germans Cinja Tillman and Svenja Muller in the semifinals of the World Championships. In a day’s time, they’d be competing for gold, as unlikely of a gold medal opportunity as the new team could have asked for just a few months ago, at a Challenger in Tlaxcala, Mexico, an event in which they didn’t make it out of the qualifier.