On the steps of city hall, Mayor David Anderson hollered a guttural “Wahhh!!!” and shot his arms into the sky to celebrate, looking like an inflatable air dancer blowing in the wind. “Four! Hundred! Million! Dollars!” he shouted, in July, to city residents in Bronson Park, a leafy plaza adorned with bronze busts and plaques honoring pioneers and philanthropists. Anonymous donors had just given wha