PORTBOU, Spain — Carles Puigdemont has escaped again. The opposition in Spain is fuming about what they say is a show of incompetence from state authorities, who failed to arrest the Catalan separatist leader when he returned to Barcelona on Thursday to speak to a few thousand supporters in a political stunt in front of the Arc de Triomf. But as is apparent here in Portbou, on the border between Catalonia and France, police have not made very big efforts to catch him after his magic-trick appearance and disappearance. Everyone from the local police to Prime Minister Pedro Sánchez in…