Non standard http frameworks (eg. Fiber)

Can you expose some functions so I can use it on frameworks that don't use the standard http handler signature or `*http.request` object such as the Fiber framework?

The library currently works with standard net/http handlers. Look at the existing signing and verification functions to understand the current interface. Research the Fiber framework to see how its request/response objects differ. The goal is to expose lower-level functions that can work with Fiber's context, likely by abstracting away the direct *http.Request dependency. Check for any existing adapter patterns or interfaces in the codebase.

索引モデルが issue の本文から書いたものです。