A Worker that fetches ranges on its own needs the same ceilings and the same
origin set as the thread that opened the package; a function cannot cross
that boundary, so the origins are resolved here and the replacement fetch is
re-supplied on the other side. Sending resolved values rather than overrides
means a Worker can only inherit a policy, never widen one.
A resolved policy in structured-cloneable form.
A Worker that fetches ranges on its own needs the same ceilings and the same origin set as the thread that opened the package; a function cannot cross that boundary, so the origins are resolved here and the replacement fetch is re-supplied on the other side. Sending resolved values rather than overrides means a Worker can only inherit a policy, never widen one.