Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-19T19:06:19+00:00	DMARC	—	INVALID	`12a658513c7d…`
2026-08-19T19:06:19+00:00	SPF	—	VALID	`0ab4965989e2…`