Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T18:02:02+00:00	DMARC	—	VALID	`bdc2327c5c09…`
2026-08-21T18:02:02+00:00	SPF	—	ABSENT	`b081350f91db…`