Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-19T16:29:49+00:00	DMARC	—	VALID	`e7068b5ebea8…`
2026-08-19T16:29:49+00:00	SPF	—	VALID	`6754c8ed248d…`