Load toolbox skills as a deepagents-ready file mapping.
Synchronous wrapper around :meth:aget_skills. See that method for full
details on base_path, backend, and the returned mapping.
Virtual directory under which skill files are placed.
Must start and end with "/". Defaults to "/skills/".
Optional deepagents backend to write the skills into via
aupload_files. When None (default), files are only
returned, for use with StateBackend seeding via
invoke(files=...).
