fix(products): improve bulk category modal and batch selection handling

- Add null check for selectAllCheckbox to avoid errors in batch-selection.js
- Replace clear existing categories toggle with radio buttons for add, replace, and clear modes
- Disable category search input and fade category list when 'clear' mode is selected
- Update mode hint text dynamically based on selected mode with explanatory messages
- Enable apply button when 'clear' mode is selected regardless of category selection
- Remove clear all categories button from modal footer
- Add event listeners for mode radio buttons to update UI and error states on change
- Initialize mode UI and apply button state on modal setup
- Bump static JS files versions for batch-selection and bulk-category-modal to 1.2 and 1.4 respectively

myproject/products/static/products/js/batch-selection.js

@@ -101,6 +101,11 @@
      * Update the "Select All" checkbox state based on individual checkboxes
      */
     function updateSelectAllCheckbox() {
+        // Проверяем наличие чекбокса перед работой с ним
+        if (!selectAllCheckbox) {
+            return;
+        }
+        
         const itemCheckboxes = document.querySelectorAll('.item-checkbox');
         const totalCheckboxes = itemCheckboxes.length;
         const checkedCheckboxes = document.querySelectorAll('.item-checkbox:checked').length;

myproject/products/static/products/js/bulk-category-modal.js

@@ -15,13 +15,13 @@
     const modal = document.getElementById('bulkCategoryModal');
     const bulkCategoryAction = document.getElementById('bulk-category-action');
     const applyBtn = document.getElementById('applyBulkCategoriesBtn');
-    const clearAllBtn = document.getElementById('clearAllCategoriesBtn');
     const categoryListContainer = document.getElementById('categoryListContainer');
     const categorySearchInput = document.getElementById('categorySearchInput');
-    const clearExistingToggle = document.getElementById('clearExistingCategoriesToggle');
     const errorAlert = document.getElementById('bulkCategoryError');
     const selectedItemsCountSpan = document.getElementById('selectedItemsCount');
     const selectedItemsBreakdownSpan = document.getElementById('selectedItemsBreakdown');
+    const modeHint = document.getElementById('bulkCategoryModeHint');
+    const categoryListSection = document.getElementById('bulkCategoryListSection');
 
     /**
      * Initialize the bulk category modal functionality
@@ -38,12 +38,27 @@
         // Event listeners
         bulkCategoryAction.addEventListener('click', handleOpenModal);
         applyBtn.addEventListener('click', handleApply);
-        clearAllBtn.addEventListener('click', handleClearAll);
-        categorySearchInput.addEventListener('input', handleCategorySearch);
+        if (categorySearchInput) {
+            categorySearchInput.addEventListener('input', handleCategorySearch);
+        }
+        
+        // Listen for mode changes
+        const modeRadios = document.querySelectorAll('input[name="bulkCategoryMode"]');
+        modeRadios.forEach(radio => {
+            radio.addEventListener('change', () => {
+                hideError();
+                updateModeUI();
+                updateApplyButtonState();
+            });
+        });
 
         // Listen for modal close to reset state
         modal.addEventListener('hidden.bs.modal', resetModalState);
 
+        // Initial UI state
+        updateModeUI();
+        updateApplyButtonState();
+
         console.log('Bulk category modal initialized');
     }
 
@@ -120,6 +135,43 @@
         selectedItemsBreakdownSpan.textContent = breakdown;
     }
 
+    /**
+     * Get current mode: add | replace | clear
+     */
+    function getCurrentMode() {
+        const checked = document.querySelector('input[name="bulkCategoryMode"]:checked');
+        return checked ? checked.value : 'add';
+    }
+
+    /**
+     * Update UI depending on selected mode
+     */
+    function updateModeUI() {
+        const mode = getCurrentMode();
+
+        if (categorySearchInput) {
+            categorySearchInput.disabled = (mode === 'clear');
+        }
+
+        if (categoryListSection) {
+            if (mode === 'clear') {
+                categoryListSection.classList.add('opacity-50');
+            } else {
+                categoryListSection.classList.remove('opacity-50');
+            }
+        }
+
+        if (modeHint) {
+            if (mode === 'add') {
+                modeHint.textContent = 'Добавленные категории будут присоединены к уже существующим.';
+            } else if (mode === 'replace') {
+                modeHint.textContent = 'Существующие категории будут полностью заменены выбранными ниже.';
+            } else if (mode === 'clear') {
+                modeHint.textContent = 'Все категории будут удалены. Список ниже будет проигнорирован.';
+            }
+        }
+    }
+
     /**
      * Load categories from server
      */
@@ -265,8 +317,15 @@
      * Update apply button state
      */
     function updateApplyButtonState() {
-        // Кнопка Применить активна только если выбрана хотя бы одна категория
-        applyBtn.disabled = selectedCategoryIds.size === 0;
+        const mode = getCurrentMode();
+
+        if (mode === 'clear') {
+            // В режиме очистки категории не требуются
+            applyBtn.disabled = false;
+        } else {
+            // Для add/replace нужна хотя бы одна выбранная категория
+            applyBtn.disabled = selectedCategoryIds.size === 0;
+        }
     }
 
     /**