Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-19T22:46:31+00:00	DMARC	—	VALID	`3c86987c9640…`
2026-08-19T22:46:31+00:00	SPF	—	VALID	`3c8428bc7ff0…`