Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T19:48:11+00:00	DMARC	—	VALID	`67ec1132c2b6…`
2026-08-16T19:48:11+00:00	SPF	—	VALID	`e37beec80b7f…`