Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-19T03:05:02+00:00	DMARC	—	VALID	`21a2563bd1db…`
2026-08-19T03:05:02+00:00	SPF	—	VALID	`b7fb7935275f…`