-- A build says which repositories it read, so a merge can find everything it affects.
--
-- A module is built from the one repository the mesh records — where its module.json lives — and some
-- modules' recipes reach into a second for the source they package: the packaging and the source are
-- allowed to live apart (catalogue's ArtifactContext). That second repository is named in the manifest
-- the build read, and the manifest the mesh *keeps* carries no build section, so nothing on the mesh
-- could say that a merge into the other repository is a change to this module at all. Two modules are
-- built from the control plane's own repository, and neither had ever been rebuilt when it moved
-- (novox/hq 04-ISSUES/131).
--
-- Nullable, like the two derived columns beside it: null is a build recorded before the mesh kept
-- this, which is not the same as a build that read nothing but its module's own repository.
alter table build add column built_contexts jsonb;