Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T20:42:41+00:00	DMARC	—	VALID	`79fa69e7b391…`
2026-08-16T20:42:41+00:00	SPF	—	VALID	`f94ab670b9aa…`