Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T05:23:22+00:00	DMARC	—	VALID	`da8f9b3d1cfe…`
2026-08-18T05:23:22+00:00	SPF	—	VALID	`c540dfeac4b1…`