Striking harbor clerks reached a tentative deal with management at the ports of Los Angeles and Long Beach on Tuesday night, settling an eight-day labor clash that has idled most of America’s biggest cargo-shipping complex.The strike cost Southern California, a region still struggling to recover from a prolonged economic slump, an estimated $8 billion, including lost wages and the value of cargo rerouted to other ports over the past week.It marked the worst cargo traffic disruption at Los Angeles and Long Beach - which together account for nearly 40 percent of all U.S. container imports - since a 10-day lockout of longshoremen at several West Coast ports in 2002.Tuesday’s accord followed a resumption of talks with last-minute prodding from Los Angeles Mayor Anthony Villaraigosa, a onetime labor activist, who announced the deal moments after union negotiators voted to approve it.Federal mediators called in to join negotiations at the mayor’s behest earlier in the day showed up just as the settlement was being reached.Officials for the International Longshore and Warehouse Workers (ILWU) Local 63 said the hundreds of clerical employees who walked off the job last Tuesday, and the thousands of longshoremen who had refused to cross their picket lines, would return to work starting Wednesday morning.The mood was jubilant outside the waterfront community center where talks were held, as smiling union members embraced and clapped one another on the back.Union officials said they expected the rank and file, who have been without a contract for more than two years, to ratify the new agreement. Details of the pact were not made public.