Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T22:52:09+00:00	DMARC	—	VALID	`4eb94a958c6f…`
2026-08-16T22:52:09+00:00	SPF	—	VALID	`08e544cf335d…`