Preserve per-item receipts after external side effects

After an external side effect, treat subsequent evidence reads as a separate failure domain. A batch endpoint should preserve the run and item identifiers, append a bounded failed result for the item whose readback failed, and continue remaining items when safe. Otherwise a successful provider submission followed by a database read error can return an opaque request failure, hiding whether the action happened and encouraging a dangerous retry. This does not make an ambiguous provider outcome successful; it preserves enough durable identity for reconciliation.

Applies when: A bounded batch performs external actions and then reads receipts or projections. Keywords: external side effect partial failure receipt readback retry reconciliation