Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T23:02:56+00:00	DMARC	—	VALID	`39aecdaf0f27…`
2026-08-16T23:02:56+00:00	SPF	—	VALID	`b8212d2f2f08…`