feat(ui): improve product search and document info section UI

- Collapse incoming document info by default with toggle animation
- Add inline cost price editing in incoming document items
- Make product search picker more compact (smaller inputs, reduced padding)
- Display new inventory lines at the top of the table
- Update product search picker styling for better visual hierarchy

myproject/inventory/static/inventory/js/inventory_detail.js

@@ -394,9 +394,9 @@
                 const emptyMessage = document.getElementById('empty-lines-message');
                 if (emptyMessage) emptyMessage.remove();
                 
-                // Добавляем новую строку
+                // Добавляем новую строку в начало таблицы
                 const newRow = self.createLineRow(data.line);
-                tbody.appendChild(newRow);
+                tbody.insertBefore(newRow, tbody.firstChild);
                 
                 // Включаем кнопку завершения
                 const completeBtn = document.getElementById('complete-inventory-btn');