Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T19:04:18+00:00	DMARC	—	VALID	`76addc3a9e1a…`
2026-08-21T19:04:18+00:00	SPF	—	VALID	`0b3a58b8d494…`