Leeren Modell-Unterordner automatisch löschen

frontend/src/tools/kalkulator3d.jsx

@@ -472,7 +472,13 @@ export default function Kalkulator3D({ toast, editData, onEditDone, mobile, setA
                     <button onClick={async () => {
                       try {
                         await api(`/tools/dateien/${f.id}`, { method:'DELETE' });
-                        setExistingFiles(p => p.filter(x => x.id !== f.id));
+                        const remaining = existingFiles.filter(x => x.id !== f.id);
+                        setExistingFiles(remaining);
+                        // Ordner löschen wenn er jetzt leer ist
+                        if (remaining.length === 0 && modelFolderId) {
+                          await api(`/tools/dateien/folders/${modelFolderId}`, { method:'DELETE' });
+                          setModelFolderId(null);
+                        }
                       } catch(e) { toast(e.message, 'error'); }
                     }} style={{ background:'transparent', border:'none', cursor:'pointer',
                       color:'rgba(255,107,157,0.5)', fontSize:14, padding:'0 2px', flexShrink:0, lineHeight:1 }}>✕</button>