Fix: Formateo PEP8 (79 cols) y limpieza flake8 en tests y examples

- Líneas >79 cols reajustadas (asserts, strings CUDE/CUDS, comentarios)
- Elimina imports y variables muertas (F401/F841), E712 (== False -> is False)
- Reordena imports en docs/conf.py

docs/conf.py

@@ -18,11 +18,11 @@
 # relative to the documentation root, use os.path.abspath to make it
 # absolute, like shown here.
 #
+import facho
 import os
 import sys
 sys.path.insert(0, os.path.abspath('..'))
 
-import facho
 
 # -- General configuration ---------------------------------------------