Common Error Codes

Code	HTTP Status	Description
INVALID_SIGNATURE	401	Authentication signature is invalid
EXPIRED_TIMESTAMP	401	Request timestamp is too old (>30s)
INSUFFICIENT_BALANCE	400	Not enough funds for operation
INSUFFICIENT_CREDITS	400	Not enough AI credits
INVALID_MARKET	404	Market ID not found
INVALID_ORDER	400	Order parameters are invalid
ORDER_NOT_FOUND	404	Order ID not found
RATE_LIMIT_EXCEEDED	429	Too many requests
INTERNAL_ERROR	500	Server error