Enhanced NXT constituent enrichment

For GiveCampus integrations and API.

Enhanced import can update additional biography including birth date, map constituent codes into affiliation data, and import class years through the enhanced education-query process with its configured year cutoff. It also imports selected custom fields. Do not assume sports/Greek-life/campus activities automatically become native activity records: confirm the NXT storage field and selected mapping, or use a mapped constituent file for unsupported data. Preserve stable constituent identity and test representative records before a broad enrichment.