ChatClient uses media

[gabz57]

Hello, I was wondering whether embabel could support files exchange with the LLM, using multimodal under the hood, would that be possible (maybe with a new method .withMedia() on PromptRunner) ?

[johnsonr]

Issues #42 and #43 relate to this. We definitely need to do it. Adding a method to PromptRunner sounds like the right approach. I haven't looked at how Spring AI handles this. We should review Spring AI and LangChain4j approaches, as well as Python frameworks, to make sure we get the right API.