Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T22:43:25+00:00	DMARC	—	VALID	`477b5b019cd1…`
2026-08-16T22:43:25+00:00	SPF	—	VALID	`9f2438a0e92e…`