fix: add HuggingFace auth to z-image-turbo downloads

[TimPietruskyRunPod]

Summary

• Adds --header="Authorization: Bearer ${HUGGINGFACE_ACCESS_TOKEN}" to the z-image-turbo model wget commands
• All other model downloads already use this header, but z-image-turbo was missing it
• Fixes the release build failure (wget exit code 3)

Changeset

N/A — build fix only.

[max4c]

Looks good — straightforward build fix adding the HuggingFace auth header to the z-image-turbo wget commands, consistent with the existing pattern for other gated models.

One minor note: the alibaba-pai/Z-Image-Turbo-Fun-Controlnet-Union repo also gets the auth header now. If that repo is public, the header is harmless (HuggingFace ignores unnecessary auth), but worth confirming it doesn't cause issues if the token lacks access to that specific org.

LGTM ✅