Create `regenerate` option AKA Message History

Currently, message history is not stored in any way. Every call to `AbstractPrompt::send()` essentially starts a new chat. On the [chatGpt web ui](https://chat.openai.com/) you can continue a conversation and refer to previous messages. Furthermore, you can say things like "Give me another example" or "Generate more".

It would be useful if the library offered the option to retain message history and thus, allow the option to "regenerate" a response.

I'm thinking something that implements the [Adapter pattern](https://refactoring.guru/design-patterns/adapter) similar to [CakePHP's Cache Engines](https://book.cakephp.org/4/en/core-libraries/caching.html#configuring-cache-engines).

Start by reading AbstractPrompt::send() and tracing how each request is assembled and dispatched. Use the issue's Adapter pattern and CakePHP Cache Engines references to define the storage boundary. Done means the library can retain conversation messages across calls and support regenerating a response, with behavior documented and covered by tests.

Written by the indexing model from the issue text.