Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-20T18:05:10+00:00	DMARC	—	VALID	`47048e3d11a5…`
2026-08-20T18:05:10+00:00	SPF	—	VALID	`b9f67c310912…`