[.Net][Feature Request]: Support prompt cache in claude

[LittleLittleCloud]

Is your feature request related to a problem? Please describe.

Claude now support prompt cache, which dramastically lower the bill if cache is hit.

https://www.anthropic.com/news/prompt-caching

Describe the solution you'd like

Add the corresponding option in claude client

Additional context

No response

[marklysze]

Very cool feature. Would be good to update the Anthropic client class in Python as well. I'll try and get that done.