CHICAGO — The championship era is over for the Chicago Sky. When Kahleah Copper left in a trade with the Phoenix Mercury last week, she took with her the final pillar of the 2021 WNBA champs, a clear punctuation mark at the end of that chapter for the franchise. This is worth mourning in itself for the city — after all, the Sky brought home Chicago’s first championship since the 2016 Cubs. But for new coach Teresa Weatherspoon and general manager Jeff Pagliocca, Copper’s exit is also clarifying. When they assumed their roles in October — splitting the coach and GM positions for the first time …
