Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-17T02:09:08+00:00	DMARC	—	VALID	`24751dd34ab2…`
2026-08-17T02:09:08+00:00	SPF	—	VALID	`859eb9e47f2f…`