Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-17T14:52:36+00:00	DMARC	—	VALID	`65b57a4eb281…`
2026-08-17T14:52:36+00:00	SPF	—	VALID	`8790b2f9cdff…`