{# Per-variant constructor for a JSON-passthrough data enum. Builds the CORE variant then `.into()`s
   it into the wrapper. DTO fields convert via `<field>_core` let bindings (one per line); primitives
   that extendr remaps are cast back to the core type at the field-init site. #}
    pub fn _factory_{{ snake }}({{ params_str }}) -> {{ name }} {
{%- for line in let_lines %}
        {{ line }}
{%- endfor %}
        {{ core_path }}::{{ variant }} { {{ field_inits }} }.into()
    }
