CANNON BALL, N.D. — Industry leaders are urging President-elect Donald Trump to make approval of the disputed Dakota Access oil pipeline a “top priority” when he takes office next month, while opponents who have protested the project for months are vowing to stay put on their sprawling North Dakota encampment despite harsh winter weather and a tribal leaders’ call to leave. The moves come after the Army Corps of Engineers declined to issue a permit for the $3.8 billion pipeline to cross under a Missouri River reservoir in southern North Dakota near the Standing Rock Sioux Reservation.