A lightweight reference to a Fact without its value.
Used during lean replay / hybrid rehydration to reconstruct graph topology without loading all fact values into memory.
Summary
Types
@type t() :: %Runic.Workflow.FactRef{ ancestry: {Runic.Workflow.Fact.hash(), Runic.Workflow.Fact.hash()} | nil, hash: Runic.Workflow.Fact.hash() }