Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T10:45:44+00:00	DMARC	—	VALID	`9b9af440a63c…`
2026-08-21T10:45:44+00:00	SPF	—	VALID	`b8212d2f2f08…`