Heads up: David Chang's latest creation, Momofuku Ko, will be open for online reservations at 10:00 a.m. today, so cancel your meetings, bookmark the URL and prepare to crash the site's server. Will the dainty new baby live up to the breathless hype that swirls around Chang's burgeoning empire? Only the quick-clicking lucky few will find out anytime soon. As we described last week, Chang deliberately decided not to take reservations by phone and created......