After five months of talks and increasingly angry rhetoric, the City of Berkeley's two largest employee unions have reached a tentative agreement on a new contract, officials announced. The pact, terms of which were not disclosed, must still be voted on by the members of Service Employees Union Local 535 and Local 790. If they approve the proposed contract, the City Council will then have to approve it on Tuesday. The unions represent the city's clerical workers, public works employees, planners, analysts and health-care staff members. The city is still negotiating with police, firefighters and electrical workers.