Version 1.3.1 - Switch to SecureLicenseClient with signature verification

- Upgraded from LicenseClient to SecureLicenseClient with HMAC-SHA256 response signature verification
- Added Server Secret configuration field for secure communication
- Added rate limit exception handling with retry time display
- Added signature verification error handling
- Added URL validation error handling (SSRF protection)
- Updated all translation files with new strings
- Compiled .mo files for all 7 language variants

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

composer.json

@@ -1,7 +1,7 @@
 {
     "name": "magdev/wc-tier-package-prices",
     "description": "WooCommerce plugin for tier pricing and package prices with Twig templates",
-    "version": "1.3.0",
+    "version": "1.3.1",
     "type": "wordpress-plugin",
     "license": "GPL-2.0-or-later",
     "authors": [
@@ -19,7 +19,7 @@
     "require": {
         "php": ">=8.3",
         "twig/twig": "^3.0",
-        "magdev/wc-licensed-product-client": "^0.1"
+        "magdev/wc-licensed-product-client": "dev-main"
     },
     "autoload": {
         "classmap": [