Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T06:26:03+00:00	DMARC	—	VALID	`ed9341f70d71…`
2026-08-18T06:26:03+00:00	SPF	—	VALID	`b1825ee51e3b…`