Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-17T12:16:06+00:00	DMARC	—	VALID	`f5e3eeeef6ac…`
2026-08-17T12:16:06+00:00	SPF	—	ABSENT	`b081350f91db…`