Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-20T12:22:08+00:00	DMARC	—	INVALID	`12a658513c7d…`
2026-08-20T12:22:08+00:00	SPF	—	VALID	`3c063eb2c873…`