WESTCHESTER Residential housing prices in Westchester County, the aggregate of all single family, 2-4 family, condo and co-op sales, showed stability. The median sales price was $425,000 in the fourth quarter, unchanged from the prior year quarter, the eighth consecutive quarter without a decline. Single family homes accounted for 57.7% of all Westchester sales and had a median sales price of $568,000, up 1.4% from the prior year quarter. The luxury single family market outpaced the overall single family market…