Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T17:12:35+00:00	DMARC	—	VALID	`82c320adfb2e…`
2026-08-18T17:12:35+00:00	SPF	—	VALID	`e220cd8eda91…`