What is the supported way to create one manual, files-based Preview deployment for an existing project through POST /v13/deployments or the Vercel CLI, while preserving every existing alias mapping?

Requirements:

• All existing project, branch, member, and custom-domain aliases must continue pointing to exactly the same deployments throughout the operation.
• The new deployment can have its own unique deployment URL.
• A separate step may add at most one new, unused test-only alias. No existing alias may be reassigned or removed.

Is skipAutoAssignDomains supported for Preview deployments? If so, what is the exact REST request parameter or SDK field, supported API/SDK version, and scope of its effects? In particular, does it suppress all automatic alias assignment, including branch and member aliases, or only some domain types?

The CLI documentation says --skip-domain must be used with --prod: https://vercel.com/docs/cli/deploy#skip-domain

If that option does not cover Preview, is there another supported API or CLI flow that meets these requirements without changing project settings? If no such guarantee exists, please clarify that limitation.

This is an informational question only. I am looking for authoritative documentation or Vercel staff clarification, rather than a trial deployment or a deploy-and-rollback workaround. No account, domain, or deployment changes are requested.