Enable Hugging Face model URL support for remote checkpoint/config downloads

[Copilot]

This issue asks for easier reproduction by allowing existing model weights to be downloaded from Hugging Face.
The update adds native handling for Hugging Face page-style file links so they work with DIRECT’s existing remote download path.

• URL handling

  • Added direct.utils.io._normalize_huggingface_url(url) to convert Hugging Face /blob/ file URLs into direct-download /resolve/ URLs.
  • Keeps non-Hugging Face URLs unchanged.

• Integration points

  • Applied normalization before redirect resolution in _get_redirect_url(...).
  • Applied normalization before text fetches in read_text_from_url(...).
  • This makes Hugging Face links usable for both remote checkpoints and remote config/text resources without changing CLI/API inputs.

• Focused test coverage

  • Extended tests/tests_utils/io_test.py with parametrized cases for:
    • model repo URLs (.../blob/... → .../resolve/...)
    • dataset repo URLs with query params preserved
    • non-Hugging Face URLs unchanged

def _normalize_huggingface_url(url: str) -> str:
    parsed_url = urllib.parse.urlparse(url)
    if parsed_url.netloc != "huggingface.co":
        return url
    if "/blob/" not in parsed_url.path:
        return url
    normalized_path = parsed_url.path.replace("/blob/", "/resolve/", 1)
    return urllib.parse.urlunparse(parsed_url._replace(path=normalized_path))

• Fixes [FR] Download weights from HuggingFace #302