KUREEN, Syria — Sa’id Agini can’t remember a time without bombing and gunfire. Having witnessed more bloodshed and destruction in his short life than most will in a lifetime, he spoke offhandedly about bombs, tanks and death. In the distance, gunfire broke through the hum of helicopter blades. “Why doesn’t that helicopter ever stop shooting?” he complained to his guests, as if talking about the weather. “We need an RPG. Would someone just shoot that thing?” He just turned 4.