Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T22:22:17+00:00	DMARC	—	VALID	`9c64c00175f5…`
2026-08-16T22:22:17+00:00	SPF	—	VALID	`5dbe2b079e97…`