Erstwhile Broadway star Anna Patterson’s grand entrance in “The Country House” may be a flop, but she sure knows how to make an exit in the TheatreWorks Silicon Valley production that opened Saturday, Aug. 29 in Mountain View. A former Berkeley Rep leading lady and 35-year stage veteran, King invests Anna not only with a vanity commensurate with her commanding presence but a wry self-awareness that makes her “I am not one whose entrances go unnoticed” as empathetic as it is funny. Self-awareness is a hallmark of all the characters in Margulies’ curious 2014 mashup of homages to Chekhov, the hallowed Williamstown Theatre Festival (in Massachusetts’ Berkshires region) and the long-standing American tradition of comedies about theater families. Some have come to participate in the summer stock season (she’s playing the title role in Shaw’s “Mrs.