Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T08:06:44+00:00	DMARC	—	VALID	`0494b037c7af…`
2026-08-21T08:06:44+00:00	SPF	—	VALID	`42de4bac93bf…`