Refactor to PSR-4: rename files and switch namespace

- Rename files to PascalCase: Product_Type → ProductType, Cart_Handler →
  CartHandler, Product_Selector → ProductSelector, Stock_Manager →
  StockManager, Admin/Product_Data → Admin/ProductData
- Switch namespace from WC_Composable_Product to Magdev\WcComposableProduct
- Update all cross-references in PHP, CSS, JS, translations, and docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

includes/ProductSelector.php

@@ -0,0 +1,77 @@
+<?php
+/**
+ * Product Selector
+ *
+ * @package Magdev\WcComposableProduct
+ */
+
+namespace Magdev\WcComposableProduct;
+
+defined('ABSPATH') || exit;
+
+/**
+ * Product Selector Class
+ *
+ * Handles rendering the product selection interface
+ */
+class ProductSelector {
+    /**
+     * Render product selector
+     *
+     * @param ProductType $product Composable product
+     */
+    public static function render($product) {
+        if (!$product || $product->get_type() !== 'composable') {
+            return;
+        }
+
+        $available_products = $product->get_available_products();
+        $selection_limit = $product->get_selection_limit();
+        $pricing_mode = $product->get_pricing_mode();
+
+        $show_images = get_option('wc_composable_show_images', 'yes') === 'yes';
+        $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 StockManager();
+
+        // 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(),
+                'price' => $available_product->get_price(),
+                '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'],
+            ];
+        }
+
+        $context = [
+            'product_id' => $product->get_id(),
+            'products' => $products_data,
+            'selection_limit' => $selection_limit,
+            'pricing_mode' => $pricing_mode,
+            'show_images' => $show_images,
+            'show_prices' => $show_prices,
+            'show_total' => $show_total,
+            'fixed_price' => $product->get_price(),
+            'fixed_price_html' => wc_price($product->get_price()),
+            'zero_price_html' => wc_price(0),
+            'currency_symbol' => get_woocommerce_currency_symbol(),
+        ];
+
+        // Render template
+        $plugin = Plugin::instance();
+        echo $plugin->render_template('product-selector.twig', $context);
+    }
+}