Heather Fink has spent her working life on film and TV sets. But years of frustration with the long hours and stagnant pay had made her reach her tipping point. She, like many of the grips, gaffers, editors, designers and other crew members who making a living producing movies and shows, was ready to go on strike at midnight on Sunday. But as the clock ticked, the International Alliance of Theatrical Stage Employees, which numbers some 60,000 members, and the Alliance of Motion Picture and Television Producers reached an agreement. Fink and her colleagues would not have to hit the picket lines.