Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T17:12:33+00:00	DMARC	—	VALID	`eff2a32837d7…`
2026-08-18T17:12:33+00:00	SPF	—	ABSENT	`b081350f91db…`