Check a parked approval by approval_id (returned in an APPROVAL_REQUIRED refusal). States: pending (the account owner has not decided — tell the user, do NOT retry the original call), executed (done — the result rides this response; never re-run the call; an approved invoice_share or quote_share keeps no link or document here, so read the current link with that tool and action 'get' as result.link_not_stored.next_call says), rejected / expired / failed (terminal — re-compose only if the user asks again). Scoped to the granting user's approvals.