Add a Hugging Face Hub repository fetcher with support for model, dataset, and space repositories, custom Hub domains, tags and revisions, and the relevant fetchgit options.
Select storage through a backend argument. Git LFS is implemented through fetchgit; Xet is the default to match Hugging Face but fails explicitly until its implementation lands.
Expose the helper from pkgs, document its API, and register evaluation and fixed-output fetch tests.
Assisted-by: OpenAI Codex (GPT-5)
