The Federal Reserve’s focus has shifted away from the job market. Investor attention should remain, however, when the January jobs report is released on Friday in the week ahead. The central bank made official last week what the investment markets already knew and have been nervous about. It is squaring up for a fight against persistent inflation. In March, the Fed is widely expected to raise its target short-term interest rate for the first time in almost four years. The strong job market and uncomfortably high inflation have made this move necessary. The agency has two statutory goals: stead…