Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-19T15:28:24+00:00	DMARC	—	VALID	`74819dc2e6d9…`
2026-08-19T15:28:24+00:00	SPF	—	VALID	`af93ec34bf9d…`