For buyers and sellers of Manhattan’s luxury properties, the fall season is on track to live up to its reputation as a typically busy period for the market. Buyers signed contracts for 31 homes in the borough asking $4 million or more last week, up from 30 in the previous period, according to Olshan Realty’s report. The totals marked the first time since early June that 30 or more properties landed inked deals in two consecutive weeks. A condo at Extell Development’s Central Park To...