Fix set_space_volumes sending wrong JSON structure (#4054)

The PUT /api/spaces/{repo_id}/volumes endpoint expects a JSON object
with a "volumes" key, but the client was sending a bare JSON array.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

src/huggingface_hub/hf_api.py

@@ -8204,7 +8204,7 @@ def set_space_volumes(
             ... )
             ```
         """
-        payload = [vol.to_dict() for vol in volumes]
+        payload = {"volumes": [vol.to_dict() for vol in volumes]}
         r = get_session().put(
             f"{self.endpoint}/api/spaces/{repo_id}/volumes",
             headers=self._build_hf_headers(token=token),