Entity resolution index: LEI → insurer slugs and website host → insurer slugs

Compact JSON, about 250 KB, for a client that wants every key at once. A client holding one identifier should fetch /resolve/lei/{lei}.json or /resolve/domain/{host}.json instead. Hosts are lower case with any leading "www." removed; a host maps only to rows that publish it as their own website, never to a subsidiary through its parent.