Native and imported gift overlap

For GiveCampus constituent data and imports.

An imported-gift transaction-ID duplicate check is scoped to imported history; it is not automatic deduplication against every native GiveCampus payment. Source labels alone do not prevent double counting. Reconcile native/imported transaction IDs, person identities and hard/soft credit semantics before importing overlap. Missing native gifts on a person can be a matching issue rather than a missing payment. Review the mapping and intended calculation before importing overlapping gifts or excluding gifts after a go-live date.