Execute combo orders

Execute multiple orders as a combo. Supports options spreads or option+perp combos. Only fill_or_kill (FOK) order type is supported.

Authentication Options:

• Signature: Include signature and signature_deadline fields in the request
• One-click session: Include x-one-click header with session hash (no signature needed)

When using one-click sessions, the signature fields can be omitted from the request.