Across New York, restaurant-goers are seeing red.  Walk into the Darby, a new, upscale restaurant with live music, and you will see garnet red. Everywhere. On the ceiling. Covering the walls. Gracing the plush, mohair booths.  "Red is a sexy color," said Steve Lewis, a partner in Lewis-Dizon, which designed the space. "More importantly, it's a color of power.