@spec accept(
  ArchAstro.Client.t(),
  ArchAstro.Types.Operations.PostApiV1InvitesAccept.Input.t()
) ::
  {:ok, ArchAstro.Types.UserInvite.t()} | {:error, ArchAstro.Error.reason()}

Accept an invite

Accepts an invite on behalf of the authenticated user and adds them to the associated team or thread. The invite key is passed in the request body rather than the URL so it never appears in access logs, Referer headers, or error-reporter URL captures.

This endpoint requires an authenticated end-user session. S2S secret-key tokens and unauthenticated requests are rejected with 401. If the authenticated user is already a member of the invite's target, the request returns 409. Both per-IP and per-user rate limits apply; exceeding either returns 429.

The accepted invite, including its ID, key, metadata, optional thread scope, creator, and creation timestamp.