3b9e82adff
With noUncheckedIndexedAccess:true, split("@")[0] returns string|undefined,
making `name` typed as string|undefined and failing the notNull staff.name
insert constraint. Fix by using ?? fallback on the array access.
Also add newStaff null guard after .returning() destructure — array
destructuring yields T|undefined with noUncheckedIndexedAccess enabled.