An armed rebellion in Russia over the weekend stunned the world and amounted to the single biggest challenge to President Vladimir V. Putin’s rule since he came to power 23 years ago. Anton Troianovski, the Moscow bureau chief for The New York Times, talks about the man who led the revolt, Yevgeny V. Prigozhin, and about what might happen next. Guest: Anton Troianovski, the Moscow bureau chief for The New York Times.