GAZA BORDER, Israel — A river of Israeli flags winds through a desert path as hundreds of people, young and old, march toward the border in a display of their determination to build new Jewish settlements atop the rubble of northern Gaza. So few buildings are left standing after Israeli bombardment that the Mediterranean is visible in the distance. Daniella Weiss, founder of the radical right-wing settler group Nachala, sums up the crowd’s intentions. “We are here on the way to new Jewish