Enhancement: Support Custom Endpoint Anthropic prompt caching

[FeepingCreature]

What features would you like to see added?

https://openrouter.ai/docs/prompt-caching

Implemented for Claude 3 only, but it's there! It would be great to have this available in LibreChat. I frequently run very long conversations that end up very expensive per query; I'd love to be able to cache.

More details

Which components are impacted by your request?

No response

Pictures

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