ISRAELI forces shelled the outskirts of the last refuge on the southern edge of the Gaza Strip, where the displaced population, penned against the border fence in their hundreds of thousands, feared a new assault with nowhere left to flee. More than half of Gaza's 2.3 million residents are now homeless and crammed into Rafah. Tens of thousands more have arrived in recent days, carrying belongings in their arms and pulling children on carts, since Israeli forces last week launched one of the biggest assaults of the war to capture adjacent Khan Younis, the main southern city. If the Israeli…