Initial implementation of WooCommerce Composable Products plugin

Implemented custom WooCommerce product type allowing customers to build their own
product bundles by selecting from predefined sets of products.

Features:
- Custom "Composable Product" type with admin interface
- Product selection by category, tag, or SKU
- Configurable selection limits (global and per-product)
- Dual pricing modes: fixed price or sum of selected products
- Modern responsive frontend with Twig templates
- AJAX add-to-cart functionality
- Full internationalization support (.pot file)
- WooCommerce settings integration
- Comprehensive documentation

Technical implementation:
- PHP 8.3+ with PSR-4 autoloading
- Twig 3.0 templating engine via Composer
- Vanilla JavaScript with jQuery for frontend interactions
- WordPress and WooCommerce hooks for seamless integration
- Security: input sanitization, validation, and output escaping
- Translation-ready with text domain 'wc-composable-product'

Documentation:
- README.md: Project overview and features
- INSTALL.md: Installation and usage guide
- IMPLEMENTATION.md: Technical architecture
- CHANGELOG.md: Version history

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

assets/js/admin.js

@@ -0,0 +1,50 @@
+/**
+ * Admin JavaScript for Composable Products
+ *
+ * @package WC_Composable_Product
+ */
+
+(function($) {
+    'use strict';
+
+    $(document).ready(function() {
+        /**
+         * Show/hide product data tab for composable products
+         */
+        $('select#product-type').on('change', function() {
+            const productType = $(this).val();
+
+            if (productType === 'composable') {
+                $('.show_if_composable').show();
+                $('.hide_if_composable').hide();
+                $('#composable_product_data').show();
+                $('.product_data_tabs .composable_options a').show();
+            } else {
+                $('.show_if_composable').hide();
+                $('#composable_product_data').hide();
+                $('.product_data_tabs .composable_options a').hide();
+            }
+        }).trigger('change');
+
+        /**
+         * Toggle criteria groups based on selected type
+         */
+        $('#_composable_criteria_type').on('change', function() {
+            const criteriaType = $(this).val();
+
+            $('.composable_criteria_group').hide();
+            $('#composable_criteria_' + criteriaType).show();
+        }).trigger('change');
+
+        /**
+         * Initialize enhanced select for categories and tags
+         */
+        if ($.fn.selectWoo) {
+            $('#_composable_categories, #_composable_tags').selectWoo({
+                placeholder: 'Select options...',
+                allowClear: true
+            });
+        }
+    });
+
+})(jQuery);