Workloads bundled with CLI versions before v4.4.4 use a strict zod enum
for `checkpoint.type` that only allows DOCKER and KUBERNETES. When a
customer's runs are routed via the compute path, those old runners
receive `type: "COMPUTE"` on `/snapshots/since/...` and `/dequeue`
responses and fail validation - blocking silent migration of existing
deployments.
The workload never reads the field - only validates the shape. Rewriting
COMPUTE -> KUBERNETES on the way out lets older runners keep parsing
while the database and internal services keep the real value. Limited to
the two workload-facing endpoints whose response includes a checkpoint;
`/continue`, `/attempts/start`, `/attempts/complete` all return shapes
without one.
Followup to #3114.
nicktrn
ddad9700d7