OptionExercise.stateIs Carta `OptionExercise` intended to represent an exercise request/workflow, including pending or canceled state, tax withholding, and money movement, distinct from the completed exercise transaction represented by `OptionExerciseTransaction`/`Exercise`? If so, should a completed OCF `EquityCompensationExercise` map only to the realized transaction structures, or should it also populate `OptionExercise`?