help request: How to dynamically pass parameters(sk-xxx) from Consumer to a ai-proxy plugin?

### Description

I am looking for a way to dynamically pass specific parameters configured at the Consumer level to a plugin executed within a Route.

Specifically, I have stored a credential (e.g., Bearer sk-xx) in the Consumer's configuration, and I need a downstream plugin in the matching route to access and use this value during the request lifecycle.

### Environment

- APISIX version (run `apisix version`): 3.15
- Operating system (run `uname -a`):
- OpenResty / Nginx version (run `openresty -V` or `nginx -V`):
- etcd version, if relevant (run `curl http://127.0.0.1:9090/v1/server_info`):
- APISIX Dashboard version, if relevant:
- Plugin runner version, for issues related to plugin runners:
- LuaRocks version, for installation issues (run `luarocks --version`):

Start by tracing how Consumer configuration is matched to a Route and exposed during the plugin request lifecycle in APISIX 3.15. Read the relevant Consumer, Route, and plugin documentation or source, focusing on the ai-proxy plugin context. Done means identifying and documenting whether the credential can be accessed safely, and how.

Written by the indexing model from the issue text.