Add Bootstrap 5 single product page layout

Add two-column responsive grid (image gallery + product summary) for
single product pages, following the same bridge pattern used for
product archives.

Key changes:
- Create content-single-product.php bridge and Twig layout template
- Add single product renderer at template_redirect priority 11
- Disable WooCommerce block compatibility layer that strips classic
  hooks when parent theme has theme.json
- Move PHP templates to woocommerce/ subfolder for cleaner structure
- Fix Twig templates to self-compute context data not passed by
  wc_get_template() (tabs, short-description, meta, rating)
- Fix Underscore.js triple-brace syntax conflict in variation template
  by wrapping in {% verbatim %}

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

woocommerce/content-single-product.php

@@ -0,0 +1,46 @@
+<?php
+/**
+ * Single Product Content — PHP Bridge to Twig
+ *
+ * Bridge file that renders the Bootstrap 5 single product template
+ * (content-single-product.html.twig) via the parent theme's TwigService
+ * instead of WooCommerce's default flat layout.
+ *
+ * WooCommerce's wc_get_template_part('content', 'single-product') uses
+ * locate_template() which finds this file in the child theme before falling
+ * back to the plugin template. Unlike wc_get_template(), wc_get_template_part()
+ * does NOT fire the woocommerce_before_template_part / woocommerce_after_template_part
+ * hooks, so the TemplateOverride class cannot intercept it — this bridge file
+ * is needed.
+ *
+ * @package WcBootstrap
+ * @since 0.1.0
+ */
+
+defined( 'ABSPATH' ) || exit;
+
+global $product;
+
+/**
+ * Hook: woocommerce_before_single_product.
+ *
+ * @hooked woocommerce_output_all_notices - 10
+ */
+do_action( 'woocommerce_before_single_product' );
+
+if ( post_password_required() ) {
+	echo get_the_password_form(); // WPCS: XSS ok.
+	return;
+}
+
+if ( class_exists( '\WPBootstrap\Twig\TwigService' ) ) {
+	$twig = \WPBootstrap\Twig\TwigService::getInstance();
+	echo $twig->render( 'content-single-product.html.twig', [
+		'product'       => $product,
+		'product_id'    => $product->get_id(),
+		'product_class' => implode( ' ', wc_get_product_class( '', $product ) ),
+	] );
+} else {
+	// Fallback: include WooCommerce's default template directly.
+	include WC()->plugin_path() . '/templates/content-single-product.php';
+}