The San Francisco Police Department is running far short of its mandated force strength, and Chief Heather Fong said Wednesday she wants the city to hire 250 recruits a year for the next three years to shore up the dwindling ranks. Police officials say the department has a total of 2,190 sworn officers but only 1,707 are available for field duty -- 264 short of the 1,971 that city voters set as a minimum in 1994. The officers unavailable for field duty are either still in the academy undergoing recruit training, assigned to the airport or on disability. "It's critical...