Resolve the principal charged for a fired event per the model's attribution strategy. Returns the @unattributed
sentinel (never silent) when nothing resolves: session/job-stamped use the supplied principal; event-expression
reads it from the payload. NOTE: an event-expression with trust !== "verified" is attacker-controllable — the
caller MUST gate it behind a verified webhook signature before trusting the result for billing.
Resolve the principal charged for a fired event per the model's attribution strategy. Returns the
@unattributedsentinel (never silent) when nothing resolves:session/job-stampeduse the supplied principal;event-expressionreads it from the payload. NOTE: anevent-expressionwithtrust !== "verified"is attacker-controllable — the caller MUST gate it behind a verified webhook signature before trusting the result for billing.