Grant Park was flooded with a sea of runners Sunday morning — many donning festive green accessories — for Chicago’s annual Shamrock Shuffle 8K race. Under overcast skies, more than 24,000 thousand runners followed the 5-mile route, snaking through the Loop. Others participated in the 2-mile scenic walk along the lakefront. “It was fantastic,” said runner Diane Rewerts, 51. “A little bit of ...