KYIV—It’s a bitterly cold Saturday night here, the temperature 10 degrees Fahrenheit and falling, and a few pedestrians are skittering down the icy sidewalks to get inside before the midnight curfew. Because the heat is out in some homes in the wake of savage Russian bombing of power facilities this month, they may have to visit one of the hundreds of warming centers in the city to get through the night. This grim winter scene is a snapshot of Russian President Vladimir Putin’s brutal strategy