Mints a session credential the payee's client uses to submit their document and selfie, and moves the verification to Pending.

Issued to the payee only; any other caller gets 404. Each call mints a fresh credential rather than returning a live one, so an abandoned attempt can simply be restarted. A verification that already reached Passed or Failed returns 400 — start a new one instead.

The session opens on the individual compliance entity of the account's principal person, so the provider sends its one-time code to the email or phone stored there. The call returns 422 with detailCode users.BiometricIdentityVerificationPrincipalRequired when the account has no principal person, and users.BiometricIdentityVerificationPrincipalComplianceEntityRequired when that person has no individual compliance entity; after fixing either, retry with a new Idempotency-Key. When the principal's compliance entity belongs to the person rather than the account, only that person may start the verification; any other caller, including an account API key, gets 403. 409 means the verification changed while starting, which a retry with a new Idempotency-Key resolves, or that an earlier attempt on another record is still under review.