Downloads a precomputed Psychic snapshot artifact. Snapshots are fixed,
already-materialized files for common rolling windows.
This endpoint does not generate missing ranges or convert missing MMDBs.

Models 1, 2, and 3 require days and currently support only 7 or
30.
date, start_date, and end_date are not supported on this endpoint.

A successful response streams the snapshot file. Transfer time still
depends on file size and client connection speed. A 404 response means
the requested snapshot artifact is not available.

License: This endpoint requires the Psychic model meter entitlement
for the requested model. Models 1, 2, and 3 also require that model's
Psychic lookback-days entitlement to cover the resolved snapshot start
date.