Karen Williams, the principal of the bespoke kitchen firm St. Charles, is branching out with her own Signature Elements collection of versatile cabinetry. The three initial pieces are meant to function as transitions from the kitchen to other spaces—family room, great room, dining room, and so on—by showcasing furniture details elegant enough to grace any part of the home. The Aldyn credenza ($18,000) has a curved-front, deco-style profile; the tall Empire cabinet ($15,000) functions as a muscularly scaled bre…