Attorney General Martha Coakley, calling the foreclosure crisis a key challenge to the state’s economic recovery, yesterday urged Massachusetts lawmakers to approve legislation meant to push more lenders into helping financially stressed homeowners save their homes. Coakley testified before the Joint Committee on Financial Services in favor of a bill that would require lenders to modify certain mortgage loans when such agreements make more economic sense than property seizures. “The single biggest thing we can do to spur economic recovery is to address the foreclosure crisis,’’ Coakley said.