End-to-end gift testing before public launch

For GiveCampus integrations and API.

Ordinary draft-campaign submissions route to payment preview, which does not create a settled donation for NXT export. Coordinate an authorized controlled live-gift test on a launched/eligible campaign to test actual processing and the NXT review/export flow. Plan any subsequent refund/reconciliation in both systems and keep match/challenge test terms explicit. Do not assume preview records export to NXT or use processor test-card numbers on production.