Security audit fixes: fn() whitelist, escaping, and performance (v0.1.4)

- WooCommerceExtension: ALLOWED_FUNCTIONS whitelist for fn() Twig function
- Notice templates: data attributes use wp_kses_post instead of raw
- Search form: esc_attr on search query value attribute
- Per-request ContextBuilder caching via static variable
- Shared wc_bootstrap_render_in_page_shell() helper (DRY)
- Removed unused WC_BOOTSTRAP_VERSION and WC_BOOTSTRAP_URL constants

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

style.css

@@ -7,7 +7,7 @@ Description: A Bootstrap 5 child theme for WP Bootstrap that overrides all WooCo
 Requires at least: 6.7
 Tested up to: 6.7
 Requires PHP: 8.3
-Version: 0.1.3
+Version: 0.1.4
 License: GNU General Public License v2 or later
 License URI: http://www.gnu.org/licenses/gpl-2.0.html
 Template: wp-bootstrap