Returns security records across all asset classes as NDJSON.
Use the filter parameter to narrow results and the fields parameter to
select which fields are returned.

When the filter targets the cache key field (isin) with an "in" operator,
the server performs direct cache lookups instead of scanning all records.
Additional filters in the same request are applied to the narrowed set.

Records are emitted in the order given by the resolution_order query
parameter (or the default order when omitted), and ISINs that appear
in more than one cache are deduped with the higher-priority asset type
winning. Asset types not listed in resolution_order are not searched.