chore: import upstream snapshot with attribution

docs/js/utils.js

@@ -0,0 +1,57 @@
+// Shared Utility Functions
+
+/**
+ * Escape HTML special characters to prevent XSS when injecting into innerHTML.
+ * Use this for any user-controlled or external data before inserting into HTML.
+ */
+function escapeHTML(str) {
+    if (typeof str !== 'string') return '';
+    return str
+        .replace(/&/g, '&')
+        .replace(/</g, '&lt;')
+        .replace(/>/g, '&gt;')
+        .replace(/"/g, '&quot;')
+        .replace(/'/g, '&#39;');
+}
+
+function copyToClipboard(text, message = 'Command copied to clipboard!') {
+    navigator.clipboard.writeText(text).then(() => {
+        showNotification(message, 'success');
+    }).catch(err => {
+        console.error('Failed to copy: ', err);
+        showNotification('Failed to copy command', 'error');
+    });
+}
+
+function showNotification(message, type = 'info') {
+    // Remove any existing notifications first
+    const existingNotifications = document.querySelectorAll('.notification');
+    existingNotifications.forEach(notif => {
+        if (notif.parentNode) {
+            notif.parentNode.removeChild(notif);
+        }
+    });
+
+    const notification = document.createElement('div');
+    notification.textContent = message;
+    notification.className = `notification notification-${type}`;
+    notification.style.cssText = `
+        position: fixed;
+        top: 20px;
+        right: 20px;
+        background: ${type === 'success' ? '#10b981' : type === 'error' ? '#ef4444' : '#3b82f6'};
+        color: white;
+        padding: 12px 24px;
+        border-radius: 6px;
+        z-index: 10000;
+        font-family: system-ui, -apple-system, sans-serif;
+        animation: slideIn 0.3s ease;
+    `;
+    
+    document.body.appendChild(notification);
+    setTimeout(() => {
+        if (notification.parentNode) {
+            notification.parentNode.removeChild(notification);
+        }
+    }, 3000);
+}