Zones for an address or a batch of points (private: POST body)

Body: {"address": "..."} (geocoded by the U.S. Census Geocoder; returns the matched address and the geocoder's tract too), {"lat": .., "lon": ..}, or {"points": [{"id", "lat", "lon"}, ...]} (up to the batch cap). Optional grade and year. Responses are never cached, and addresses and points are never written to the application's logs.