A.2:4.4 - Admit Only Exact System-Role-Kind Domains

U.Kind is too broad as the assigned-kind participant domain of an assignment species. Each bounded system-role vocabulary declares one local domain whose candidates are local kinds satisfying the recognition conditions above. For example:

JournalReviewSystemRoleKindDomain : U.Kind
  definitionProvenance: JournalReview-2026 (comparison cue only)
  candidateValueKind: U.Kind
  criterion:
    the candidate kind has U.System candidates, a stable assignable
    work-facing membership condition, useful boundary probes, and
    a continuity rule recovered under C.3

A direct assignment species uses that local domain as the ValueKind of its declaration-local AssignedSystemRoleKindSlot. The slot therefore rejects CoolingPumpKind, ShortAssignmentKind, and arbitrary local kinds. This is local C.3 typed use, not admission of U.Kind as a durable public root.