At first light, the shoreline at El Médano looked more like a landfill than the heart of Cabo’s bay. Locals showed up with gloves and trash bags anyway. By day’s end, they had filled well over a thousand bags with debris washed down by swollen arroyos after Lorena’s rains. Officials moved in with trucks and front loaders, while beach flags stayed black. What happened overnight, and what it will take to get Cabo’s busiest beach truly back, tells a…