Create Template Version

Clone a template into a new version. The clone is a FULL COPY of all columns (goals, settings, name+description, skills) PLUS the source's attachments (re-pointed at the new template id). The new row joins the lineage via version_root_id and is inactive by default; admin promotes when ready.

Attachment rows are duplicated (same file_url — S3 bytes are shared, no re-upload needed). Mutating one version's attachment list (add/remove) only affects that version's row; the file in S3 stays referenced by any version that still points at it.

Body (optional): version_label: human label for the new version. Defaults to "v{N}" where N is the next sequential number in the lineage.