Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-20T06:06:44+00:00	DMARC	—	VALID	`fd6633ff4b11…`
2026-08-20T06:06:44+00:00	SPF	—	VALID	`4d4815dd4357…`