Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T10:03:28+00:00	DMARC	—	VALID	`b5a5fe9fdfe7…`
2026-08-18T10:03:28+00:00	SPF	—	VALID	`aa92511c9bab…`