Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T00:48:29+00:00	DMARC	—	VALID	`288c43bb52c1…`
2026-08-21T00:48:29+00:00	SPF	—	VALID	`95f7188dcbb5…`