Update the draft graph of the envelope under review
Same contract as PUT /v1/envelopes/{id}/draft, scoped to the token’s envelope: any subset of participants, fields, and policy, applied in one transaction (allowed in draft and review status only — envelopes are immutable after send). participants requires fields in the same call. expectedVersion is checked strictly when supplied.
Authorizations
HMAC-signed review token (minted into the envelope's review URL at creation), as a bearer token or a token query param. Capabilities are split per token: a read token grants view + draft editing, a send token grants the dispatch action only — so a forwarded review link can be shared read-only. Scoped to exactly one envelope; never valid as a signer credential.