Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-17T07:49:59+00:00	DMARC	—	VALID	`c4ec7984a6db…`
2026-08-17T07:49:59+00:00	SPF	—	VALID	`a24afa92f1f7…`