POZNAN, Poland (AP) — A generation ago, Poland rationed sugar and flour while its citizens were paid one-tenth what West Germans earned. Today, the economy of the country has edged past Switzerland to become the world’s 20th largest with more than $1 trillion in annual output. It’s a historic leap from the post-Communist ruins of 1989-90 to European growth champion, which economists say has lessons on how to bring prosperity to ordinary people — and that the Trump administration says should be recognized by Poland’s presence at a summit of the Group of 20 leading economies later this year. The transformation is reflected in people like Joanna Kowalska, an engineer from Poznan, a city of around 500,000 people midway between Berlin and Warsaw. She returned home after five years in the U.S. “I get asked often if I’m missing something by coming back to Poland, and, to be honest, I feel it’s the other way around,” Kowalska said.…