A LOT GOES INTO preparing for the Pacific Northwest Ballet’s monthlong performance of "The Nutcracker." The company and its many behind-the-scenes employees have been hard at work, perfecting dances, preparing costumes, and making sure everything is just so before the dancers step out from behind the curtain to sold-out crowds. Every detail is important, from the littlest mouse’s whiskers to Clara’s nightgown. The Sugarplum Fairy would be proud.