Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T11:17:00+00:00	DMARC	—	VALID	`5d3f90c84b70…`
2026-08-21T11:17:00+00:00	SPF	—	VALID	`6413876b1784…`