Those who follow professional sports are familiar with the term “league minimum” — i.e., a still-exorbitant salary that the barely-good-enough make to ride pine on a given team. “League maximum,” however, is something of an unheard-of term — unless you’re familiar with the WNBA’s pay scale.Yesterday, before Sue Bird’s Seattle Storm — who’ve already clinched a playoff birth –lost an overtime heartbreaker to the league-leading Phoenix Mercury, the All-Star point guard signed a two-year contract extension that will keep her with the Storm through the 2011 season. The contract was for the league maximum: $101,500 annually. Or, put another way, a lot less than many City of Seattle employees make to announce project delays and identify the latest in cement-pouring technology.