Release version 1.2.8 - Currency display and data deletion fixes

Fixed two important bugs reported in v1.2.7:

Bug 1: Currency Symbol Missing in Admin Headers and Placeholders
- Table headers now show "Price (CURRENCY)" instead of just "Price"
- Input placeholders include currency symbol (e.g., "9.99 $")
- Better UX for multi-currency stores

Bug 2: Variation Pricing Data Not Deleted Properly (Critical)
- Empty pricing arrays were being saved instead of deleted
- Fixed save logic to check if arrays are empty after filtering
- Properly deletes post meta when all entries are removed
- Affects simple products, variable parents, and variations

Technical changes:
- Updated all table headers with currency symbol display
- Modified all render methods to pass currency_symbol to templates
- Updated Twig templates to use currency in placeholders
- Fixed save_tier_package_fields() and save_variation_pricing_fields()
- Added !empty() checks before update_post_meta() calls

🤖 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/magdev/wc-tier-package-prices
  * Description: Add tier pricing and package prices to WooCommerce products with configurable quantities at fixed prices
- * Version: 1.2.7
+ * Version: 1.2.8
  * Author: Marco Graetsch
  * Author URI: https://src.bundespruefstelle.ch/magdev
  * Text Domain: wc-tier-package-prices
@@ -23,7 +23,7 @@ if (!defined('ABSPATH')) {
 
 // Define plugin constants
 if (!defined('WC_TPP_VERSION')) {
-    define('WC_TPP_VERSION', '1.2.7');
+    define('WC_TPP_VERSION', '1.2.8');
 }
 if (!defined('WC_TPP_PLUGIN_DIR')) {
     define('WC_TPP_PLUGIN_DIR', plugin_dir_path(__FILE__));