ExcepcionAlarma._esValida matched ANY exception tipo against an
occurrence, treating it as a user skip. Only the 'skipNext' tipo
existed until now, but the next commits reuse the same model to
record scheduling-reliability failures per alarm (so the alarms list
can surface them via ultimaExcepcionPara) -- without this guard, a
recorded failure would be silently treated as if the user asked to
skip that occurrence, corrupting scheduling. Adds tipo constants to
ExcepcionAlarma for the upcoming failure kinds.
FreeTLab
88bd251eba