AccessDelegation is the LangSmith access this sandbox was granted, absent when.
type SandboxResponseAccessDelegation structAccessDelegation is the LangSmith access this sandbox was granted, absent when it has none. Either mode can appear: a grant is reported as requested, except that INHERIT requested by a creator who is itself delegated is stored as EXPLICIT carrying that creator's own ceiling, so the value always describes what this sandbox can reach rather than what was asked for.