Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-19T00:28:12+00:00	DMARC	—	VALID	`c4ec7984a6db…`
2026-08-19T00:28:12+00:00	SPF	—	VALID	`876c427fe12b…`