GGB By default, nobody — each party is appointed for its own scope, and the seams between scopes fall to the owner. That is the role owner-side project management exists to fill: one seat that holds the design freeze, chairs coordination between architect, kitchen consultant, engineers and contractor, controls variations against tendered rates, and reports cost, date and risk in the owner's language. Whether you fill it in-house or engage it, someone has to sit in it.
From Choosing Your Restaurant Architect, Kitchen Consultant and Contractor — the full reading, with the method behind this answer.