One AI audit event in an execution’s trail (RAO constraint 6): a model
invocation, a routing decision, or a human review action. kind is the
event discriminant (ai_invocation / ai_routing_decision /
ai_review_required / ai_review_resolved); payload holds the
kind-specific fields as JSON.
A persisted recurring-run timer for a saved flow (roadmap E11). Keyed by the
saved template slug so a flow has at most one schedule. next_run_at is the
next instant the background scheduler should fire (recomputed after each run
from frequency + anchor_at); None when disabled.