标记被Cloudflare AI Gateway缓存的请求

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Routine Checks

• I have confirmed there are no similar issues currently
• I have confirmed I have upgraded to the latest version
• I have thoroughly read the project README and confirmed the current version cannot meet my needs
• I understand and am willing to follow up on this issue, assist with testing and provide feedback
• I understand and acknowledge the above, and understand that project maintainers have limited time and energy, issues that do not follow the rules may be ignored or closed directly

Feature Description

使用Cloudflare AI Gateway代理请求时，标记被Cloudflare AI Gateway缓存的请求。根据CF的文档，被缓存的请求会返回带有cf-aig-cache-status: HITheader的响应。

To check whether a response comes from cache or not, cf-aig-cache-status will be designated as HIT or MISS.
per https://developers.cloudflare.com/ai-gateway/features/caching/

Use Case

这样能知道请求有没有实际花钱。