Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T21:39:19+00:00	DMARC	—	VALID	`d9d8a87b606d…`
2026-08-16T21:39:19+00:00	SPF	—	VALID	`b8212d2f2f08…`