Many Manhattan housing metrics showed improvement from the year-ago quarter, driven by increased resale activity from the release of pent-up demand accumulated before the U.S. election last November. The resale market, accounting for 84% of co-op and condo sales, was a better indicator of the state of the market as legacy contracts for new development sales reflected conditions of several years ago.Resales showed a 7.7% jump to 2,429 from the same period last year outpacing the 4.2% gain in resale inventory to 4,859 listings…