examples/agent.py imports the private model_router._http helper

[TheCoder30ec4]

Problem

examples/agent.py calls the chosen model with from model_router._http import request_json. Examples are what people copy, and _http is private and may change.

Suggested fix

Either:

• give the example its own ~10-line urllib helper, or
• (bigger) propose a public Router.complete() in a separate issue.

Done when

• No example imports anything starting with _
• examples/agent.py still runs with an OPENROUTER_API_KEY