SEATTLE — Boeing factory workers voted against the company’s latest contract offer and remain on the picket lines six weeks into a strike that has stopped production of the aerospace giant’s bestselling jetliners. Local union leaders in Seattle said 64% of members of the International Association of Machinists and Aerospace Workers who cast ballots Wednesday voted against accepting the contract offer . “After 10 years of sacrifices, we still have ground to make up, and we’re hopeful to do so by