Implement Phase 3: single product page templates (Bootstrap 5)

Add 21 Twig template overrides for the single product page:

Product layout:
- product-image: gallery with thumbnail strip, img-fluid rounded
- title: h1 entry-title
- price: fs-3 fw-bold with sale del/ins markup
- short-description: lead text-body-secondary
- meta: dl row with SKU, categories, tags
- rating: Bootstrap Icon stars with half-star, review count link
- stock: badge (bg-success/bg-danger/bg-warning) per status
- sale-flash: badge bg-danger fs-6
- share: hook-only wrapper
- product-attributes: table-sm table-striped

Related/upsells:
- related, up-sells: section with product loop grid

Tabs:
- tabs: nav-tabs + tab-content with fade transitions
- description: tab-pane with prose content
- additional-information: tab-pane with attributes hook

Add to cart (4 product types + variation JS):
- simple: input-group quantity + btn-primary btn-lg
- variable: form-select per attribute + variation display
- grouped: table-borderless with quantity per child product
- external: btn-outline-primary with external link icon
- variation: Underscore.js script templates (Bootstrap-styled)
- variation-add-to-cart-button: quantity + submit with hidden fields

CSS additions: gallery thumbnail hover, variation selector spacing.

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

templates/single-product/add-to-cart/grouped.html.twig

@@ -0,0 +1,84 @@
+{#
+ # Grouped Product Add to Cart (Bootstrap 5 Override)
+ #
+ # Add-to-cart form for grouped products: table of child products with quantities.
+ #
+ # Expected context:
+ #   product                  - WC_Product_Grouped object
+ #   grouped_products         - Array of child WC_Product objects
+ #   grouped_product_columns  - Array of column definitions
+ #   quantites_required       - Whether quantities are required
+ #   show_add_to_cart_button  - Whether to show the submit button
+ #
+ # WooCommerce PHP equivalent: single-product/add-to-cart/grouped.php
+ #
+ # @package WcBootstrap
+ # @since 0.1.0
+ #}
+
+{{ do_action('woocommerce_before_add_to_cart_form') }}
+
+<form class="cart grouped_form" action="{{ product.get_permalink()|esc_url }}" method="post" enctype="multipart/form-data">
+    <div class="table-responsive mb-4">
+        <table class="woocommerce-grouped-product-list group_table table table-borderless align-middle">
+            {{ do_action('woocommerce_grouped_product_list_before') }}
+
+            {% for grouped_product in grouped_products %}
+                {% set child_id = grouped_product.get_id() %}
+                <tr id="product-{{ child_id }}" class="{{ grouped_product.get_stock_status() }}">
+                    <td class="woocommerce-grouped-product-list-item__quantity" style="width: 140px;">
+                        {% if grouped_product.is_purchasable() and grouped_product.is_in_stock() %}
+                            {% include 'global/quantity-input.html.twig' with {
+                                input_id: 'quantity_' ~ child_id,
+                                input_name: 'quantity[' ~ child_id ~ ']',
+                                input_value: 0,
+                                min_value: 0,
+                                max_value: grouped_product.get_max_purchase_quantity()|default(0),
+                                step: 1,
+                                placeholder: '0',
+                                inputmode: 'numeric',
+                                classes: 'qty',
+                                readonly: false,
+                                type: 'number',
+                                args: { product_name: grouped_product.get_name() }
+                            } %}
+                        {% endif %}
+                    </td>
+
+                    <td class="woocommerce-grouped-product-list-item__label">
+                        <label for="quantity_{{ child_id }}">
+                            {% if grouped_product.is_visible() %}
+                                <a href="{{ grouped_product.get_permalink()|esc_url }}" class="text-decoration-none">
+                                    {{ grouped_product.get_name()|esc_html }}
+                                </a>
+                            {% else %}
+                                {{ grouped_product.get_name()|esc_html }}
+                            {% endif %}
+                        </label>
+                    </td>
+
+                    <td class="woocommerce-grouped-product-list-item__price text-end">
+                        <span class="price">
+                            {{ grouped_product.get_price_html()|raw }}
+                        </span>
+                    </td>
+                </tr>
+            {% endfor %}
+
+            {{ do_action('woocommerce_grouped_product_list_after') }}
+        </table>
+    </div>
+
+    {% if show_add_to_cart_button is not defined or show_add_to_cart_button %}
+        {{ do_action('woocommerce_before_add_to_cart_button') }}
+
+        <input type="hidden" name="add-to-cart" value="{{ product.get_id() }}" />
+        <button type="submit" class="btn btn-primary btn-lg single_add_to_cart_button">
+            {{ product.single_add_to_cart_text() }}
+        </button>
+
+        {{ do_action('woocommerce_after_add_to_cart_button') }}
+    {% endif %}
+</form>
+
+{{ do_action('woocommerce_after_add_to_cart_form') }}