feat: Add license management and tabbed settings (v0.3.0)

- Implement license management using magdev/wc-licensed-product-client
- Reorganize settings page into License, Default Settings, Integrations tabs
- Add license validation and activation via AJAX
- Frontend features require valid license (admin works always)
- Update translations with German (de_CH) for license strings

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

assets/css/admin.css

@@ -4,4 +4,122 @@
  * @package WP_FediStream
  */
 
-/* Admin styles will be added here */
+/* Settings page tabs */
+.nav-tab-wrapper + .fedistream-settings-content {
+    margin-top: -1px;
+}
+
+.fedistream-settings-content {
+    background: #fff;
+    border: 1px solid #c3c4c7;
+    border-top: none;
+    padding: 20px;
+}
+
+/* Active tab styling */
+.wrap .nav-tab-wrapper .nav-tab-active {
+    background: #fff;
+    border-bottom-color: #fff;
+}
+
+/* License status banner */
+.fedistream-license-status {
+    margin-bottom: 20px;
+}
+
+.fedistream-license-status .dashicons {
+    color: inherit;
+}
+
+.fedistream-license-status.notice-success .dashicons {
+    color: #00a32a;
+}
+
+.fedistream-license-status.notice-error .dashicons {
+    color: #d63638;
+}
+
+.fedistream-license-status.notice-warning .dashicons {
+    color: #dba617;
+}
+
+.fedistream-license-status.notice-info .dashicons {
+    color: #72aee6;
+}
+
+/* License form buttons */
+#fedistream-license-form .button .dashicons {
+    font-size: 16px;
+    width: 16px;
+    height: 16px;
+    line-height: 1.3;
+}
+
+/* License message display */
+#fedistream-license-message {
+    padding: 10px 15px;
+}
+
+#fedistream-license-message p {
+    margin: 0;
+}
+
+/* Dashboard stats grid */
+.fedistream-stats {
+    display: grid;
+    grid-template-columns: repeat(4, 1fr);
+    gap: 20px;
+    margin: 20px 0;
+}
+
+.fedistream-stat-box {
+    background: #fff;
+    padding: 20px;
+    border: 1px solid #ccd0d4;
+    border-radius: 4px;
+}
+
+.fedistream-stat-box h3 {
+    margin: 0 0 10px;
+}
+
+.fedistream-stat-box p {
+    font-size: 2em;
+    margin: 0;
+    color: #2271b1;
+}
+
+/* Quick actions */
+.fedistream-quick-actions {
+    background: #fff;
+    padding: 20px;
+    border: 1px solid #ccd0d4;
+    border-radius: 4px;
+    margin: 20px 0;
+}
+
+/* Info box */
+.fedistream-info {
+    background: #fff;
+    padding: 20px;
+    border: 1px solid #ccd0d4;
+    border-radius: 4px;
+}
+
+/* Responsive adjustments */
+@media screen and (max-width: 782px) {
+    .fedistream-stats {
+        grid-template-columns: repeat(2, 1fr);
+    }
+
+    #fedistream-license-form .button {
+        display: block;
+        margin: 10px 0 0 0 !important;
+    }
+}
+
+@media screen and (max-width: 480px) {
+    .fedistream-stats {
+        grid-template-columns: 1fr;
+    }
+}

assets/js/admin.js

@@ -8,7 +8,115 @@
     'use strict';
 
     $(document).ready(function() {
-        // Admin scripts will be added here
+        // License validation functionality
+        initLicenseValidation();
     });
 
+    /**
+     * Initialize license validation AJAX handlers.
+     */
+    function initLicenseValidation() {
+        var $validateBtn = $('#fedistream-validate-license');
+        var $activateBtn = $('#fedistream-activate-license');
+        var $spinner = $('#fedistream-license-spinner');
+        var $message = $('#fedistream-license-message');
+
+        if (!$validateBtn.length) {
+            return;
+        }
+
+        // Validate license button
+        $validateBtn.on('click', function(e) {
+            e.preventDefault();
+            performLicenseAction('fedistream_validate_license', 'Validating...');
+        });
+
+        // Activate license button
+        $activateBtn.on('click', function(e) {
+            e.preventDefault();
+            performLicenseAction('fedistream_activate_license', 'Activating...');
+        });
+
+        /**
+         * Perform license AJAX action.
+         *
+         * @param {string} action AJAX action name.
+         * @param {string} loadingText Loading button text.
+         */
+        function performLicenseAction(action, loadingText) {
+            var originalText = $validateBtn.text();
+
+            // Show loading state
+            $spinner.addClass('is-active');
+            $validateBtn.prop('disabled', true);
+            $activateBtn.prop('disabled', true);
+            $message.hide();
+
+            $.ajax({
+                url: ajaxurl,
+                type: 'POST',
+                data: {
+                    action: action,
+                    nonce: fedistreamLicenseNonce
+                },
+                success: function(response) {
+                    $spinner.removeClass('is-active');
+                    $validateBtn.prop('disabled', false);
+                    $activateBtn.prop('disabled', false);
+
+                    if (response.success) {
+                        showMessage('success', response.data.message);
+                        // Reload page to show updated status
+                        setTimeout(function() {
+                            window.location.reload();
+                        }, 1500);
+                    } else {
+                        showMessage('error', response.data.message || 'An error occurred.');
+                    }
+                },
+                error: function(xhr, status, error) {
+                    $spinner.removeClass('is-active');
+                    $validateBtn.prop('disabled', false);
+                    $activateBtn.prop('disabled', false);
+                    showMessage('error', 'Request failed. Please try again.');
+                }
+            });
+        }
+
+        /**
+         * Show a message to the user.
+         *
+         * @param {string} type Message type: 'success', 'error', 'warning', 'info'.
+         * @param {string} text Message text.
+         */
+        function showMessage(type, text) {
+            var classMap = {
+                'success': 'notice-success',
+                'error': 'notice-error',
+                'warning': 'notice-warning',
+                'info': 'notice-info'
+            };
+
+            var noticeClass = classMap[type] || 'notice-info';
+
+            $message
+                .removeClass('notice-success notice-error notice-warning notice-info')
+                .addClass('notice ' + noticeClass)
+                .html('<p>' + escapeHtml(text) + '</p>')
+                .show();
+        }
+
+        /**
+         * Escape HTML entities.
+         *
+         * @param {string} text Text to escape.
+         * @return {string} Escaped text.
+         */
+        function escapeHtml(text) {
+            var div = document.createElement('div');
+            div.textContent = text;
+            return div.innerHTML;
+        }
+    }
+
 })(jQuery);