Hundreds of Aramark workers at Fenway Park are on strike and planning to stay out for all of a homestand between the Boston Red Sox and the Los Angeles Dodgers starting Friday night. Concession workers had set a deadline of noon Friday for an agreement with the Local 26 chapter of the Massachusetts and Rhode Island hotel, casino, airport and food services workers union. They want better pay and protection against technology changes. Union officials ask fans attending the homestand to support the food and beer workers by not buying anything inside Fenway.