Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T12:18:13+00:00	DMARC	—	VALID	`e16820a4d462…`
2026-08-21T12:18:13+00:00	SPF	—	VALID	`f6f967c1523b…`