A line of cars snaked through the garbage-strewn streets of the Shuafat refugee camp in east Jerusalem, as Palestinians waited to pass an Israeli checkpoint. Alaa Gharab was sunk down behind the steering wheel at an intersection that resembled a ragged war zone, littered with burnt tires, gutted appliances and the charred carcass of a car. It was the first time she could leave the camp since last Saturday night, when a Palestinian gunman fired at the checkpoint from close range, killing a 19-year-old female Israeli soldier and severely wounding a security guard before disappearing toward Shuaf…