Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T11:35:30+00:00	DMARC	—	VALID	`be9baa2986d7…`
2026-08-18T11:35:30+00:00	SPF	—	ABSENT	`b081350f91db…`