After being lured to the Gulf of Maine’s warming waters to feed, young sea turtles are trapped and cold-stunned as temperatures drop. A major rescue and rehabilitation response is underway to save them.By Teresa TomassoniOver the last few weeks, volunteers have braved bitter winds and freezing temperatures to patrol Cape Cod’s bayside beaches at night, sweeping their flashlight beams along the last high-tide line marked with mounds of seaweed, searching for signs of life.