Add kluster.ai LLM API service

[jmayermsi]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

Please add this service to available models, I am looking to utilize this model provider for R1 access.

https://docs.kluster.ai/get-started/start-api/

2. Additional context or comments

No response

3. Can you help us with this feature?

• I am interested in contributing to this feature.