Handles SCIM 2.0 POST-based .search endpoints per RFC 7644 Section 3.4.3.
Supports both resource-specific search (e.g. POST /Users/.search) and
cross-resource search (POST /.search) that combines Users and Groups.
Summary
Functions
Performs a resource-specific search (e.g. POST /Users/.search).
Searches across all resource types (POST /.search).