Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-19T02:33:30+00:00	DMARC	—	VALID	`6da73cc664a8…`
2026-08-19T02:33:30+00:00	SPF	—	VALID	`a1860d7cf518…`