Release version 1.1.5 - Critical bug fix for plugin activation

CRITICAL FIX: Resolved fatal error that prevented plugin activation in
versions 1.1.3 and 1.1.4. The add_cart_quantity_css() method was attempting
to access WooCommerce cart object during wp_head action, causing failures
when WooCommerce wasn't fully initialized or on admin pages.

Fixes:
- Plugin activation error in v1.1.3 and v1.1.4
- Fatal error when WooCommerce cart object not available
- Frontend errors on admin pages
- Issues during plugin initialization

Technical Changes:
- Added function_exists('WC') check before accessing WooCommerce
- Added is_admin() check to prevent CSS injection on admin pages
- Enhanced add_cart_quantity_css() with proper guards
- Line 191: if (!function_exists('WC') || !WC()->cart || is_admin())

Root Cause:
The add_cart_quantity_css() method (added in v1.1.3) hooks into wp_head
but didn't properly check if WooCommerce cart was available, causing
errors during plugin activation and on admin pages.

Updated Files:
- includes/class-wc-tpp-cart.php (enhanced error checking)
- wc-tier-and-package-prices.php (version 1.1.5)
- composer.json (version 1.1.5)
- CHANGELOG.md (v1.1.5 section)
- All translation files (.pot, .po, .mo) updated to version 1.1.5

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

wc-tier-and-package-prices.php

@@ -4,7 +4,7 @@
  * Plugin Name: WooCommerce Tier and Package Prices
  * Plugin URI: https://src.bundespruefstelle.ch/wc-tier-package-prices
  * Description: Add tier pricing and package prices to WooCommerce products with configurable quantities at fixed prices
- * Version: 1.1.4
+ * Version: 1.1.5
  * Author: Marco Graetsch
  * Author URI: https://src.bundespruefstelle.ch/magdev
  * Text Domain: wc-tier-package-prices
@@ -22,7 +22,7 @@ if (!defined('ABSPATH')) {
 }
 
 // Define plugin constants
-define('WC_TPP_VERSION', '1.1.4');
+define('WC_TPP_VERSION', '1.1.5');
 define('WC_TPP_PLUGIN_DIR', plugin_dir_path(__FILE__));
 define('WC_TPP_PLUGIN_URL', plugin_dir_url(__FILE__));
 define('WC_TPP_PLUGIN_BASENAME', plugin_basename(__FILE__));