Duplication

A common business need is to draft a finalized document, and later create a very similar new document with only minor value changes.
Instead of starting from scratch, you can implement this as a duplication flow with session export and import.

Typical usage:

1. End-user finalizes the original document.
2. Your backend exports the builder session with GET /api/builder/sessions/{session_id}/export.
3. You store the ZIP archive in your own storage.
4. When the end-user clicks "Duplicate", your backend imports the archive with POST /api/builder/sessions/import and creates a new builder session.
5. You redirect the end-user to the new session URL and they adjust only the values that differ.

Important behavior:

• Import always creates a completely new builder session.
• The original exported session remains unchanged.
• Handlers are integration-specific and must be provided again on import.