Clone non-owned default core materials before editing

Clone default core materials so you get owned entries you can edit, optionally in bulk and with prices.

1. Default core materials in the admin library are non-owned and cannot be edited directly.

   ✓ Checked in the product on 9 October 2026

2. Cloning can be done in bulk across groups.

   ✓ Checked in the product on 12 October 2026

3. Prices can be cloned along with the material.

   ✓ Checked in the product on 12 October 2026

4. Only owned (cloned) entries become editable.

   ✓ Checked in the product on 9 October 2026