Implement version 0.0.3 features

- Add file attachment support for product versions (Media Library)
- Add version auto-detection from uploaded filenames
- Implement secure customer downloads with hash verification
- Add license key copy-to-clipboard functionality
- Redesign customer licenses page with card-based UI
- Fix product versions meta box visibility for non-licensed types
- Add DownloadController for secure file delivery
- Update CLAUDE.md roadmap and session history

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

assets/js/frontend.js

@@ -0,0 +1,90 @@
+/**
+ * WC Licensed Product - Frontend Scripts
+ *
+ * @package Jeremias\WcLicensedProduct
+ */
+
+(function($) {
+    'use strict';
+
+    var WCLicensedProductFrontend = {
+        init: function() {
+            this.bindEvents();
+        },
+
+        bindEvents: function() {
+            $(document).on('click', '.copy-license-btn', this.copyLicenseKey);
+        },
+
+        /**
+         * Copy license key to clipboard
+         */
+        copyLicenseKey: function(e) {
+            e.preventDefault();
+
+            var $btn = $(this);
+            var licenseKey = $btn.data('license-key');
+
+            if (!licenseKey) {
+                return;
+            }
+
+            // Use modern clipboard API if available
+            if (navigator.clipboard && navigator.clipboard.writeText) {
+                navigator.clipboard.writeText(licenseKey)
+                    .then(function() {
+                        WCLicensedProductFrontend.showCopyFeedback($btn, true);
+                    })
+                    .catch(function() {
+                        WCLicensedProductFrontend.fallbackCopy(licenseKey, $btn);
+                    });
+            } else {
+                WCLicensedProductFrontend.fallbackCopy(licenseKey, $btn);
+            }
+        },
+
+        /**
+         * Fallback copy method for older browsers
+         */
+        fallbackCopy: function(text, $btn) {
+            var $temp = $('<textarea>');
+            $('body').append($temp);
+            $temp.val(text).select();
+
+            try {
+                var success = document.execCommand('copy');
+                WCLicensedProductFrontend.showCopyFeedback($btn, success);
+            } catch (err) {
+                WCLicensedProductFrontend.showCopyFeedback($btn, false);
+            }
+
+            $temp.remove();
+        },
+
+        /**
+         * Show feedback after copy attempt
+         */
+        showCopyFeedback: function($btn, success) {
+            var message = success
+                ? wcLicensedProduct.strings.copied
+                : wcLicensedProduct.strings.copyFailed;
+
+            var $feedback = $('<span class="copy-feedback"></span>')
+                .text(message)
+                .addClass(success ? 'success' : 'error');
+
+            $btn.after($feedback);
+
+            setTimeout(function() {
+                $feedback.fadeOut(300, function() {
+                    $(this).remove();
+                });
+            }, 1500);
+        }
+    };
+
+    $(document).ready(function() {
+        WCLicensedProductFrontend.init();
+    });
+
+})(jQuery);