Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T22:54:28+00:00	DMARC	—	VALID	`5fe0a483d7bf…`
2026-08-16T22:54:28+00:00	SPF	—	VALID	`660e88e30512…`