Target said Wednesday it plans to invest $5 billion across stores next year in an effort to win back customers as the retail giant reported its 12th-straight month of weak or falling sales. Same-store sales fell 2.7% in the three months ended Nov. 1.  Customers visited Target less often and spent less while they were there, with foot traffic plunging 2.2% and average transactions falling 0.5% from the previous year. Shares in Target fell 0.9% Wednesday. The stock is down 36% so far this year. “