Optionallimits: MemoryLayerRegistryLimitsVerify the content address (and manifest when present), then store.
Check-evidence blobs (08-review.md §8.4): the IDS spec + report files
whose blake3 digests a provenance manifest's checks entries carry
(specDigest / report). Content-addressed and verified on write.
Optional so caller-supplied stores predating evidence keep working —
the route answers 501 when the store lacks them.
Persist a published layer; file.header.id is its blake3 id.
Minimal store surface the merge flow needs; implementations own durability.