Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-20T13:55:42+00:00	DMARC	—	VALID	`b7992aca7df9…`
2026-08-20T13:55:42+00:00	SPF	—	VALID	`f4d7fc850518…`