Implement comprehensive stock management integration (v1.1.0)

Added complete inventory tracking system for composable products:
- Stock validation during product selection and add-to-cart
- Automatic stock deduction on order completion/processing
- Automatic stock restoration on order cancellation/refund
- Stock status indicators with visual feedback (In stock, Low stock, Out of stock)
- Prevention of out-of-stock item selection
- Low stock warnings when 5 or fewer items remain
- Order notes documenting all stock changes

New files:
- includes/Stock_Manager.php: Core stock management logic

Modified files:
- includes/Cart_Handler.php: Integrated stock validation
- includes/Product_Selector.php: Added stock info to product data
- includes/Plugin.php: Added Stock_Manager to includes
- templates/product-selector.twig: Stock status display
- assets/css/frontend.css: Stock indicator styling
- languages/*.pot/*.po: 8 new translatable strings

Version bumped to 1.1.0 with updated CHANGELOG.

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

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

includes/Product_Selector.php

@@ -33,9 +33,14 @@ class Product_Selector {
         $show_prices = get_option('wc_composable_show_prices', 'yes') === 'yes';
         $show_total = get_option('wc_composable_show_total', 'yes') === 'yes';
 
+        // Get stock manager for stock information
+        $stock_manager = new Stock_Manager();
+
         // Prepare product data for template
         $products_data = [];
         foreach ($available_products as $available_product) {
+            $stock_info = $stock_manager->get_product_stock_info($available_product->get_id());
+
             $products_data[] = [
                 'id' => $available_product->get_id(),
                 'name' => $available_product->get_name(),
@@ -43,6 +48,11 @@ class Product_Selector {
                 'price_html' => $available_product->get_price_html(),
                 'image_url' => wp_get_attachment_image_url($available_product->get_image_id(), 'thumbnail'),
                 'permalink' => $available_product->get_permalink(),
+                'stock_status' => $stock_info['stock_status'],
+                'in_stock' => $stock_info['in_stock'],
+                'stock_quantity' => $stock_info['stock_quantity'],
+                'managing_stock' => $stock_info['managing_stock'],
+                'backorders_allowed' => $stock_info['backorders_allowed'],
             ];
         }