Jim Harbaugh announced Wednesday that the 49ers will start their hot hand at quarterback Sunday against the St. Louis Rams. No not the guy who has connected on 25 of his last 27 passes with four touchdowns and zero interceptions. His hand must have cooled since his concussion against the Rams three weeks ago. Harbaugh is going with Colin Kaepernick, who has excited the 49er faithful by helping San Francisco thump NFC playoff contenders Chicago and New Orleans. But Harbaugh also insists that Alex Smith is the starting quarterback and hasn’t done anything to lose his position. It seems the …