Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T02:46:38+00:00	DMARC	—	VALID	`f5e5c45f8a32…`
2026-08-18T02:46:38+00:00	SPF	—	VALID	`2ef74056e304…`