Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-20T07:39:50+00:00	DMARC	—	VALID	`ed41bd1dc7a4…`
2026-08-20T07:39:50+00:00	SPF	—	VALID	`bb3473bf079e…`