For decades, the writer Ludmilla Petrushevskaya was banned in the Soviet Union. She wrote stories about domestic despair and Soviet censors demanded optimism. Petrushevskaya’s writing was just too dark, but today she’s a living legend in Russia. And she’s always reinventing herself. Her newest endeavor? Cabaret. Recently Petrushevskaya visited New York City and sang for an audience of Russian émigrés. Kiera Feldman reports.