Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T22:21:27+00:00	DMARC	—	INVALID	`12a658513c7d…`
2026-08-18T22:21:27+00:00	SPF	—	VALID	`66137a5f0bf5…`