Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-09-03T14:42:50+00:00	DMARC	—	VALID	`19ae4b3729c0…`
2026-09-03T14:42:50+00:00	SPF	—	VALID	`02e7fa096da6…`