Two layers. The integration suite runs a real pg-boss against a real
Postgres and proves the semantics the policies rest on: that a bare
singletonKey under the default policy de-duplicates nothing, that
exclusive suppresses a duplicate while the first job is queued AND while
it is active, that short suppresses only while queued and admits a send
once the job is active, and that a distinct key always enqueues.
It also pins the two facts that make the fix reach a running instance:
createQueue does not change the policy of a queue that already exists,
and updateQueue refuses a policy change, so the reconcile is required.
The unit guard couples each enqueue site to its registrar entry. The key
and the policy live in different files with nothing in the type system
holding them together, so deleting an entry would leave the call site
looking correct while it silently stopped working.
