Constituent API email type and primary versus Identifiers screen

For GiveCampus integrations and API.

The v2 Constituent API emails array stores email_type, address and primary on the constituent’s email-address records. POST and PUT both process these values, and the v2 response serializes them. Use lowercase schema keys and send at most one primary email; the processor reports an error for multiple primaries. Constituent Identifiers under Online Giving reporting is a different external-ID/email mapping screen, so its two displayed fields do not mean the API discarded email type or primary status. Verify through the supported v2 read response and per-item errors. v1 uses a different preferred/business/other email structure; do not mix schemas. PUT replaces supplied email collections under its documented rules, so preserve the intended complete set rather than treating it as an arbitrary partial email patch.