Release version 1.3.0 - License management and settings sub-tabs

Breaking Changes:
- PHP 8.3+ now required (previously 7.4+)

Added:
- License management integration using magdev/wc-licensed-product-client
- Settings page split into General and License sub-tabs
- License validation and activation via AJAX
- PHP version check with admin notice

Changed:
- Refactored settings class to use modern WooCommerce patterns
- Updated all translations with new license-related strings

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

assets/css/admin.css

@@ -154,3 +154,52 @@ label[for^="wc_tpp_restrict_to_packages_"] {
 input[id^="wc_tpp_restrict_to_packages_"] + .description {
     display: none;
 }
+
+/* License Status Styling */
+.wc-tpp-license-active {
+    color: #46b450;
+    font-weight: 600;
+}
+
+.wc-tpp-license-inactive {
+    color: #dc3232;
+    font-weight: 600;
+}
+
+.wc-tpp-license-expired {
+    color: #ffb900;
+    font-weight: 600;
+}
+
+#wc-tpp-license-spinner {
+    float: none;
+    margin-top: 0;
+    vertical-align: middle;
+}
+
+#wc-tpp-validate-license,
+#wc-tpp-activate-license {
+    margin-right: 8px;
+}
+
+#wc-tpp-license-status-container {
+    margin-bottom: 10px;
+    padding: 10px 15px;
+    background: #f9f9f9;
+    border-left: 4px solid #ccc;
+    border-radius: 2px;
+}
+
+#wc-tpp-license-status-container.valid {
+    border-left-color: #46b450;
+    background: #f0fff0;
+}
+
+#wc-tpp-license-status-container.invalid {
+    border-left-color: #dc3232;
+    background: #fff0f0;
+}
+
+#wc-tpp-license-status-container small {
+    color: #666;
+}