By Daniel Chavkin Seattle punched its ticket back to the postseason in dramatic fashion. For the first time since 2001, the Mariners are headed to the playoffs. Seattle officially clinched a playoff spot with a dramatic win over the Athletics on Friday night Cal Raleigh, pinch hitting with two outs in the bottom of the ninth inning, blasted a walk-off homer to right field to send the Mariners to the postseason in epic fashion. By clinching, the Seattle has officially snapped its 21-year postseason drought, which was the longest such drought among the four major sports. That record now belongs …