Question to people talking about the various alternatives that already exist for this: does anyone know if there's something like OpenRouter that's open source and that, either as the only interface or preferably as an optional alternative to a web interface, lets you use a standard non-AI chat app (ideally Signal, more likely WhatsApp) as the interface?

Edit: I'd still be grateful for a reply with any recommendations or other options, but ChatGPT has given me a few things to look into when I'm at my PC - https://chatgpt.com/share/6873a9b5-ea8c-800c-b111-96b5f27a09...