Was he even invited? When the American president arrives in a foreign land, customarily there’s a red carpet. But when Air Force One arrived in Hangzhou Saturday for the G-20 Summit beginning today, there was a carpet, but no stairs, forcing President Obama to clamber down what appeared to be built-in steps from a lower exit. Then his aides nearly scrapped with Chinese officials over their press restrictions. But Obama downplayed the drama, saying there’s often protocol friction during such visits, and ended Saturday with a chummy moonlight stroll with Chinese President Xi Jinping.