Delta Air Lines Inc. is launching a $12.1 million expansion of the gates it operates at Seattle-Tacoma International Airport. Port of Seattle commissioners approved the airline's fast-tracked gate reconfiguration project Tuesday, saying it's needed to alleviate a gate shortage that's about to get worse. Atlanta-based Delta's latest project comes just a week after opening its $24 million Sky Club lounge in the same area. Delta (NYSE: DAL) worked with the Port of Seattle and Sea-Tac to reconfigure…