Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-17T10:57:30+00:00	DMARC	—	VALID	`c779dfc60a7a…`
2026-08-17T10:57:30+00:00	SPF	—	ABSENT	`b081350f91db…`