Derive Polymarket CLOB credentials

Given your EOA private key, the server hits Polymarket’s auth endpoints to derive (or fetch) your CLOB HMAC credentials, stores them, and returns the public-safe metadata. Run this once per user before your first Polymarket order.

Your private key is used in-memory by the server only to perform the derivation and is not persisted. For maximum trust, you can call derivePolymarketCredentials() from the SDK which is equivalent.