Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-19T04:06:26+00:00	DMARC	—	VALID	`5d709b62c3c4…`
2026-08-19T04:06:26+00:00	SPF	—	VALID	`cd696f284cc3…`