One Circle operation as it stands right now: the identity and prepared
operation held in circle_operations, the phase held beside them, and the
upload steps already completed, joined from circle_operation_uploads.
A journal whose recorded state contradicts itself or the commit it
describes. Produced by the journal’s own validation; workflow errors wrap
it at the operation boundary.
Where one Circle operation stands. Persisted on its own, apart from the
operation it describes: this is what a transition rewrites, and the prepared
operation is what a transition leaves alone.