DENVER — In search of a new look for his ailing lineup, Mets manager Carlos Mendoza inserted his best hitter into the leadoff spot Monday. It was Juan Soto’s first leadoff appearance since May 30, 2021, with the Nationals. During his Mets tenure, Soto has hit almost exclusively in the No. 2 hole. “It’s something I have been thinking about the last few days with a lot of players on the injured list,” Mendoza said before the Mets faced the Rockies at Coors Field. “It just got to the point, watching how teams use their bullpen — not so much Juan, but the guys behind him — is forcing us to make decisions a lot earlier in games.” Bo Bichette had largely been hitting leadoff since Francisco Lindor was placed on the injured list 1 ½ weeks ago. Juan Soto swings during the Mets’ May 4 game against the Rockies. AP Bichette slid to No. 2 with Soto’s elevation to leadoff. Mendoza broached the subject with Soto on Sunday and was encouraged that Soto bought into the idea.…