Class ArtifactsClient

Mint an artifact ingest session for delivering a content-addressed bundle to one serving device. The returned grant carries the one-time sessionToken the caller streams the bytes with (no later read returns it).

The content-addressed digests a DEVICE currently holds on disk (ADR-0008 WP4.1). The agent reports its store contents after every delivery and at startup; the backend keeps them as DEVICE--ARTIFACT--> edges.

This is the per-device idempotency signal. get cannot serve that purpose: ArtifactsTable is keyed by digest ALONE, so a registration made by any earlier application or device answers "yes" for a device whose store is empty — which is how a deploy came to skip delivery to a device that then failed closed forever (CA-4).

Read an ArtifactRecord by digest (presence / idempotency probe). digest is URL-encoded into the path (sha256: contains a :).

Poll an artifact ingest session (the delivery waiter's poll target). The artifact session is an IngestSessionRecord, so it is read through the shared storage-session route; the session token is never returned here.

Register (put-if-absent) the ArtifactRecord for a delivered digest. Idempotent — the first writer persists {digest, kind, size, source:'ingest', refCount:0}; refCount is driven up later at release cut.