In the dizzying world of New York fashion, Runway is the Holy Grail. Overseen with a finely manicured fist by Miranda Priestly (Meryl Streep), the magazine is a fearsome gauntlet for anyone who wants to succeed in the fashion world. A stint as Miranda's assistant could blast open the doors for recent college graduate Andy Sachs (Anne Hathaway). More college drab than haute couture, she stands a…