swift-huggingface: Complete Swift Hub client with resume support and Python cache integration

AI Impact Summary

This release delivers a ground-up Swift client for Hugging Face Hub, addressing prior reliability gaps, cache fragmentation, and opaque authentication by introducing a TokenProvider and OAuth flow. It provides complete Hub API coverage, robust file transfers with progress tracking and resume support, and a Python-compatible cache to share models between Swift and Python clients, reducing duplicate downloads. The integration path targets swift-transformers as the replacement for HubApi, so teams should plan migration and validate download, list, and model retrieval workflows across both ecosystems.