The Phase 3 live gate deadlocked every FetchAndCache deploy: DeploymentArtifactGrpcService
gated on Status==Sealed, but central seals a deployment only AFTER every node acks Applied,
and a FetchAndCache node cannot ack until it has fetched the artifact — seal-needs-ack ->
ack-needs-fetch -> fetch-needs-sealed. The node's fetch reached central and passed the
shared-key interceptor, then got a clean NotFound; the #485 apply-failure path correctly
kept last-known-good, but the deploy could never seal.
Direct mode reads the same ArtifactBlob from SQL while the row is still AwaitingApplyAcks,
so the serve path must too. Drop the Sealed gate: serve any deployment whose blob is
non-empty (unknown id / empty blob still collapse to NotFound — existence-hiding + #485).
Access is already gated by the interceptor, so there is no reason to hide a non-sealed
deployment a node is legitimately applying. The Task 2 'non-sealed -> NotFound' test flips
to 'non-sealed with a blob is served'.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Streams a sealed deployment's ArtifactBlob to a fetching driver node in
128-KiB chunks (matching the LocalDb cache chunk size). Unknown id, a
non-sealed deployment, and a zero-length blob all collapse to one
indistinguishable NotFound — existence-hiding plus the #485 serve-side guard
(never stream empty bytes as a valid empty config). The impl is named
DeploymentArtifactGrpcService to avoid colliding with the generated
DeploymentArtifactService container type.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW