Approve Submission Challenge

Return the EIP-712 ReleaseApproval a signed-session principal must sign to approve this submission, and the header to send it back in (X-EM-Approval). Read-only: it approves nothing and releases nothing.

Approve is the step that RELEASES the escrow, and it does so with no signature of its own. A session grant is a bearer for its window, so the bridge refuses approve on the session alone and asks for a second signature that names THIS submission — copying a session header out of a log must not buy the ability to pay out a worker.

Principals authenticated with ERC-8128 do not need this: their request is already signed per-request.