Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-17T02:00:49+00:00	DMARC	—	VALID	`1241f18c2c04…`
2026-08-17T02:00:49+00:00	SPF	—	VALID	`f77c1088d4b3…`