Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T13:20:05+00:00	DMARC	—	VALID	`d6f6143c407a…`
2026-08-21T13:20:05+00:00	SPF	—	VALID	`1ff73dcee55c…`