Is the Boston-area housing market cooling off at last?

Sales are down. Prices are leveling off. New listings are plummeting.A report out Tuesday from the Greater Boston Association of Realtors shows that it is all but certain now: the region’s long-hot housing market is cooling off fast.Only 1,092 homes were sold in September in the 64 cities and towns GBAR tracks, a 12.7 percent…