赋能 AI 代理：V1 系统账单结算 (ETL-D API)

Language models, especially in billing and payments, must operate with factual accuracy. Traditional LLMs can generate plausible responses based on learned patterns but may suffer from 'hallucination,' producing incorrect or fabricated information. The use of the '/v1/system/billing/checkout' endpoint mitigates this issue by providing deterministic output that directly interfaces with the system, enabling the LLM to accurately perform billing-related functions such as generating a Stripe Checkout URL for purchasing credits. Furthermore, this designated endpoint acts as deterministic middleware, ensuring consistency and reliability.