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.

   ✓ Am 9. Oktober 2026 im Produkt geprüft

2. Cloning can be done in bulk across groups.

   ✓ Am 12. Oktober 2026 im Produkt geprüft

3. Prices can be cloned along with the material.

   ✓ Am 12. Oktober 2026 im Produkt geprüft

4. Only owned (cloned) entries become editable.

   ✓ Am 9. Oktober 2026 im Produkt geprüft