Feature: Add unread message notifications to admin badge

- Add isRead boolean field to Message model (default: false)
- Create migration to update database schema
- Update admin notifications to count unread messages
- Display unread message count in notification badge tooltip
- Admins now see all notifications: pending orders, design approvals, photo requests, unread messages
- Color-coded tooltip: orange (orders), blue (designs), clay (photos), pink (messages)

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

src/components/AdminNotificationsBadge.tsx

@@ -7,6 +7,7 @@ interface AdminNotificationsBadgeProps {
   pendingOrders: number;
   designApprovals: number;
   photoRequests: number;
+  unreadMessages: number;
 }
 
 export default function AdminNotificationsBadge({
@@ -14,6 +15,7 @@ export default function AdminNotificationsBadge({
   pendingOrders,
   designApprovals,
   photoRequests,
+  unreadMessages,
 }: AdminNotificationsBadgeProps) {
   const [showTooltip, setShowTooltip] = useState(false);
   const ref = useRef<HTMLDivElement>(null);
@@ -61,6 +63,12 @@ export default function AdminNotificationsBadge({
               <span className="font-bold text-clay">{photoRequests}</span>
             </div>
           )}
+          {unreadMessages > 0 && (
+            <div className="flex items-center justify-between py-2 px-3 bg-surface rounded">
+              <span className="text-muted">Unread messages</span>
+              <span className="font-bold text-splash-pink">{unreadMessages}</span>
+            </div>
+          )}
         </div>
       )}
     </div>