* test(skill_manager): update sandbox cache path expectations
adjust sandbox cache tests to match absolute path resolution in
list_skills for sandbox runtime.
verify sandbox-cached skills cannot be deactivated via set_skill_active
by asserting a PermissionError, and keep active-only listing behavior
intact.
add coverage for show_sandbox_path=false to ensure local skills still
override cached metadata while sandbox-only skills retain cached paths.
* test(skill_manager): tighten local skill path assertions