Review of the registry work found the seat node-scoped: a second `distribution` on another
machine resolved cleanly there, and only afterwards did the mesh notice `artifact-store`
offered by two nodes, with every consumer elsewhere refusing to choose. A node-scoped
requirement with one candidate installs that candidate, so anything that wanted the store
beside it would have raised a fresh, empty store on the wrong machine first.
The claim is mesh-scoped in mesh-catalog now; this holds the catalogue's manifest to it —
a second store anywhere is refused by name, where it is assigned.