Ford Motor Co. and a South Korean company would have to create more than 5,000 full-time jobs at a planned electric pickup truck factory and battery manufacturing plant in Tennessee or pay back at least part of a $500 million state grant for the project, according to a lease approved Thursday by a regional board. The Megasite Authority of West Tennessee’s board of directors voted to approve the lease during a meeting to discuss the $5.6 billion project to build electric F-Series pickups and batteries at a 3,600-acre (1,460-hectare) parcel of land in rural Stanton, northeast of Memphis.