Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T21:20:29+00:00	DMARC	—	VALID	`31d6377d873e…`
2026-08-18T21:20:29+00:00	SPF	—	VALID	`b8212d2f2f08…`