Create an authorization

Creates an `Authorization` for a single prior-authorization request. An authorization tracks requirement collection, payer submission, receipt, and final outcome. Create one authorization per payer submission you want Collate to manage. The request pins the provider, payer, service code, and final-submission policy. Collate resolves the route internally. Optional initial answers are merged before the case is created. The response is the current authorization snapshot — questionnaire, requirements, and `nextAction` — at version `1`. Creating an authorization does not submit anything to the payer. Inspect the returned snapshot, resolve any blockers, and call [Confirm an authorization](api:POST/v1/prior-authorizations/{authorization_id}/confirm) only when the authorization exposes a confirmable `nextAction`. Reuse the same `Idempotency-Key` to retry a create safely. Reusing it with a different request body returns `409 idempotency_key_reused`. ## Returns Returns the newly created authorization.