Soft-credit gift history imports

For GiveCampus constituent data and imports.

Represent a soft credit as an imported gift-history row assigned to the credited constituent, with a stable distinct Gift Transaction ID, positive Amount, Payment Date and an identifiable Gift Type such as “Soft Credit.” Map those fields under Gifts; the import schema does not expose a separate soft-credit amount column. Review the import’s unique-key configuration so the soft-credit row is not mistaken for or overwrites the hard-credit row. To have it count toward donor status, include that exact Gift Type in the school’s donor-status gift-type configuration. This is recognition history, not a second processed payment; avoid adding hard and soft credits together as if they were separate cash receipts.