Implement Phase 9 & reusable components; skip Phase 8 (emails)

Phase 8 (Emails) skipped: WooCommerce email rendering uses
wc_get_template_html() which bypasses the Twig pipeline entirely.
Email customization deferred to plugins or block email editor.

Phase 9 - Supplementary (7 templates):
- Brand description with thumbnail, taxonomy archive delegate
- Brands A-Z shortcode with alphabetical index navigation
- Single brand thumbnail shortcode
- REST API OAuth login and grant-access forms
- Back-in-stock notification form with email input

Reusable Components (6 templates):
- price: product price display with sale handling
- rating: star rating with Bootstrap Icons (filled/half/empty)
- address-card: billing/shipping address card with edit link
- status-badge: contextual order status badges
- quantity-input: +/- input group widget
- form-field: universal form field renderer (text/select/textarea/checkbox)

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

templates/single-product/back-in-stock-form.html.twig

@@ -0,0 +1,65 @@
+{#
+ # Back in Stock Form (Bootstrap 5 Override)
+ #
+ # Notification signup form shown on out-of-stock product pages.
+ #
+ # Expected context:
+ #   product_id       - Product ID
+ #   is_visible       - Whether the form is visible (not hidden)
+ #   show_email_field - Whether to show the email input
+ #   show_checkbox    - Whether to show the privacy opt-in checkbox
+ #   button_class     - CSS class for the submit button
+ #
+ # WooCommerce PHP equivalent: single-product/back-in-stock-form.php
+ #
+ # @package WcBootstrap
+ # @since 0.1.0
+ #}
+
+<div class="wc_bis_form card{% if not is_visible %} d-none{% endif %} mt-3"
+     data-bis-product-id="{{ product_id }}">
+    <div class="card-body">
+        <h3 id="wc_bis_form_heading_{{ product_id }}" class="h6 mb-3">
+            {{ __('Want to be notified when this product is back in stock?') }}
+        </h3>
+
+        <form method="post" novalidate aria-labelledby="wc_bis_form_heading_{{ product_id }}">
+            <div class="d-flex gap-2 mb-3">
+                {% if show_email_field %}
+                    <label for="wc_bis_email_{{ product_id }}" class="visually-hidden">
+                        {{ __('Email address to be notified when this product is back in stock') }}
+                    </label>
+                    <input type="email"
+                           name="wc_bis_email"
+                           class="form-control"
+                           placeholder="{{ __('Enter your e-mail') }}"
+                           id="wc_bis_email_{{ product_id }}"
+                           required
+                           aria-required="true" />
+                {% endif %}
+
+                <button type="submit"
+                        name="wc_bis_register"
+                        class="btn btn-primary flex-shrink-0">
+                    <i class="bi bi-bell me-1" aria-hidden="true"></i>
+                    {{ __('Notify me') }}
+                </button>
+            </div>
+
+            {% if show_checkbox %}
+                <div class="form-check">
+                    <input type="checkbox"
+                           class="form-check-input"
+                           name="wc_bis_opt_in"
+                           id="wc_bis_opt_in_{{ product_id }}" />
+                    <label class="form-check-label small" for="wc_bis_opt_in_{{ product_id }}">
+                        {{ wc_replace_policy_page_link_placeholders(wc_get_privacy_policy_text('registration'))|wp_kses_post }}
+                    </label>
+                </div>
+            {% endif %}
+
+            {{ wp_nonce_field('wc_bis_signup', 'wc_bis_nonce') }}
+            <input type="hidden" name="wc_bis_product_id" value="{{ product_id }}" />
+        </form>
+    </div>
+</div>