Iteration 1 (acceptance 2, the heart): the content-addressed blueprint store
(Registry::put_blueprint/get_blueprint under runs/blueprints/), the store write
at the sweep persist seam, the extracted shared run_blueprint_member, and
`aura reproduce <family-id>` re-deriving every persisted member bit-identically
from the stored blueprint. acceptance 1 (graph introspect --content-id) and 3
(Tier-1 id stability) deferred to plan 0094b.
refs #158
Brummel
a6d3774d04