Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-20T12:52:47+00:00	DMARC	—	VALID	`8a676dd4283b…`
2026-08-20T12:52:47+00:00	SPF	—	VALID	`0cc8e55e241b…`