Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T17:00:11+00:00	DMARC	—	VALID	`a5852de709fe…`
2026-08-21T17:00:11+00:00	SPF	—	VALID	`a396a7a3034b…`