Sumsub — Resolve currency and chain

One endpoint answers both halves, and the two halves look nothing alike:

`type=fiat`	`type=crypto`
Flat list of ISO 4217 codes, fetched live	Thousands of assets across a hundred-plus chains
No chain, no contract, no ambiguity	Over a thousand symbols exist on more than one chain
Resolving = "is it in the list"	Resolving = `(symbol, chain, [contract])` → exactly one asset

Most of this skill is about the crypto side, because that is where transactions silently go wrong. Fiat is a membership test.

Endpoint

Verb	Path	Purpose
`GET`	`/resources/kyt/currency?type=crypto`	The crypto catalogue. Static server-side; safe to cache for a session.
`GET`	`/resources/kyt/currency?type=fiat`	Fiat codes, assembled live from the rates provider.