Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T20:04:01+00:00	DMARC	—	INVALID	`7ee351e3c6cd…`
2026-08-16T20:04:01+00:00	SPF	—	VALID	`b8212d2f2f08…`