Hugging Face Unity API integration with Unity projects via Inference API

AI Impact Summary

This change enables direct AI model calls from Unity via a Hugging Face Unity API package that wraps the Hugging Face Inference API. It is installed from a Git URL and configured with an API key in the Unity API Wizard, with the option to swap model endpoints to use different models. The sample code demonstrates asynchronous SentenceSimilarity calls and callback-based result handling. Key considerations include securing the API key in client builds and monitoring quotas and latency to avoid gameplay impact.