The online giant on Tuesday said it would raise the minimum wage to $15 an hour for all of its United States workers. It said the pay increase would include part-time workers and those hired through temporary agencies. The company said it would also lobby Washington to raise the federal minimum wage... Amazon has come under increased scrutiny for the wages and conditions of its work force, particularly at the fulfillment centers where it packages and sorts orders, and with the contract drivers who make last-mile deliveries. Some workers at the grocery chain Whole Foods, which Amazon bought last year, have recently made a push to organize a union. The wage increase comes as Amazon’s fortunes...have ballooned. Amazon’s market capitalization passed $1 trillion last month...