deliver method
Actuates delivery for request. Ok optionally carries the RECEIPT (a PR
url, an export path), merged into the terminal state=complete write under
grid.result.<nodePath>.*. Failed routes the terminal route node to
SUPERVISION: a failed delivery NEVER silently advances. A THROWING method is
treated exactly as Failed (the per-work fail-closed posture).
Implementation
@override
Future<StepOutcome> deliver(DeliveryRequest request) async {
requests.add(request);
if (throwNext) throw StateError('delivery blew up');
return outcome;
}