Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T15:07:30+00:00	DMARC	—	VALID	`b9a342621f17…`
2026-08-18T15:07:30+00:00	SPF	—	VALID	`88bc1f47296c…`