The Starbucks workers’ union said on Friday it is escalating an indefinite strike to more than 120 stores and 85 cities, demanding higher pay and staffing levels at the coffee chain.The walkout, set to be the longest strike in the history of Starbucks, began on its Red Cup Day on Nov. 13 with 65 stores and more than 40 cities.The strike comes on Black Friday, the busiest time of year for retailers when shoppers hunt for bargains on everything from food and groceries to apparel and appliances.Striking Starbu ...