fix(hf): include folder deletions in git commit payload

[kszucs]

Which issue does this PR close?

Closes #.

Rationale for this change

HuggingFace git-based repos support deleting folders via the deletedFolders field in the commit API. The deleter was silently discarding directory-entry paths (those ending with /) instead of passing them through.

What changes are included in this PR?

• Pass directory paths to commit_git as DeletedFolder entries instead of ignoring them
• Update the unit test to assert files and folders are separated correctly in the commit payload
• Skip test_remove_all_with_prefix_exists for HF git-based repos via a feature-gated scheme check instead of a fragile runtime probe write

Are there any user-facing changes?

Yes — deleting a directory path on a git-based HF repo now correctly removes the folder rather than silently doing nothing.

AI Usage Statement

Claude Code was used to assist with this change.