Park City Opera will raise the curtain on its 2026 summer season Saturday with “American Opera at Promontory” at the Promontory Club’s The Shed. The performance starts at 6 p.m. and will feature three guest vocalists and a chamber orchestra, conducted by Musical Director Benjamin Beckman, said Artistic Director Lena Goldstein. “The Shed is a gorgeous terrace, outdoor amphitheater with phenomenal acoustics for what we’ll have,” she said. “People …