Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-17T22:11:22+00:00	DMARC	—	VALID	`a94846a5206d…`
2026-08-17T22:11:22+00:00	SPF	—	VALID	`3c328e8876a9…`