Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T21:07:51+00:00	DMARC	—	VALID	`996a6399c30b…`
2026-08-16T21:07:51+00:00	SPF	—	VALID	`baf8cadfe63f…`