text: Title: [ENH] Error propagation in files mode
  Body: ```python
  df = pd.DataFrame({'s': ['a', 'b', 'c'], 'd': ['b', 'c', 'a']})
  graphistry.edges(df, 'WRONG', 'd').plot(as_files=True, render=False)
  ```
  
  Will not hint at the binding error, while `as_files=False` will. Both should -- unclear if PyGraphistry inspecting validity on viz create response, or validity not being set.