corrected type mismatch

Web/app.py

@@ -6451,11 +6451,6 @@ def item_edit(id):
     anschaffungs_kosten = sanitize_form_value(request.form.get('anschaffungskosten'))
     reservierbar = 'reservierbar' in request.form
 
-    # Filter 1-3 für alle Objekte
-    filter1 = expand_filter_selection(sanitize_form_value(request.form.getlist('filter')), 1)
-    filter2 = expand_filter_selection(sanitize_form_value(request.form.getlist('filter2')), 2)
-    filter3 = sanitize_form_value(request.form.getlist('filter3'))
-
     code_4 = sanitize_form_value(request.form.get('code_4'))
     individual_codes_raw = request.form.get('individual_codes', '')
 
@@ -6490,16 +6485,26 @@ def item_edit(id):
         return redirect(redirect_target)
 
     if show_library_features:
+        # LIBRARY ITEM: Process ISBN/Medientyp/Category, preserve existing filters
         isbn_raw = sanitize_form_value(request.form.get('isbn', ''))
         item_isbn = normalize_and_validate_isbn(isbn_raw) if isbn_raw else ''
         item_type = sanitize_form_value(request.form.get('item_type_input', current_item.get('ItemType', 'Buch')))
         library_category = sanitize_form_value(request.form.get('library_category', ''))
         images = current_item.get('Images', [])
+
+        filter1 = current_item.get('Filter', [])
+        filter2 = current_item.get('Filter2', [])
+        filter3 = current_item.get('Filter3', [])
     else:
+        # NON-LIBRARY (INVENTORY) ITEM: Process Filter 1-3 from form
         item_isbn = current_item.get('ISBN', '')
-        item_type = current_item.get('ItemType', 'other')
+        item_type = 'other'
         library_category = current_item.get('library_category', '')
 
+        filter1 = expand_filter_selection(sanitize_form_value(request.form.getlist('filter')), 1)
+        filter2 = expand_filter_selection(sanitize_form_value(request.form.getlist('filter2')), 2)
+        filter3 = sanitize_form_value(request.form.getlist('filter3'))
+
         images_to_keep = request.form.getlist('existing_images')
         original_images = current_item.get('Images', [])
         images = [img for img in original_images if img in images_to_keep]
@@ -6539,7 +6544,6 @@ def item_edit(id):
                         images.append(new_filename)
                     except Exception as e:
                         app.logger.error(f"Image error for item {id}: {e}")
-
     if ort and ort not in it.get_predefined_locations():
         it.add_predefined_location(ort)