EpochProvenance

Where the state on a transition row was read (S§C.11.3).

A decision element no longer owns its timing: a modeler calls decide(reason) at a point they choose, or requestDecision(reason) to have the epoch taken in an event of the element's own. The two differ in a way a consumer of the trajectory cannot otherwise recover, and it is exactly the way that matters to a consumer.

IMMEDIATE — the state was read at the caller's call site. The model was inside some other event action at the time, so the caller warranted the state's consistency (R2b); the library did not.

DEFERRED — the state was read in the element's own zero-delay event, so the model was between events. Weaker than a scheduled epoch's guarantee — such an event lands at the current time later in the event order, not at the end of the instant — but it is a guarantee rather than a warrant.

An enum rather than a boolean because a third position is real and measured, not merely possible. DeferredEpochPositionProbeTest shows a decision requested from the executive's condition-scan phase landing after every model event at the instant, where a deferred one lands among them by priority — stronger quiescence, and a fact about the executive rather than about any subsystem. Nothing currently produces it, so there is no third value; widening a published field later is the thing this shape avoids if something ever does.