Add server control buttons to dashboard with confirmation dialogs

- Add ConfirmModal component for stop/restart confirmations
- Add start/stop/restart buttons to ServerCard (moderator/admin only)
- Add confirmation dialogs to ServerDetail for stop/restart actions
- Add btn-sm CSS class for smaller buttons

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

gsm-frontend/src/pages/Dashboard.jsx

@@ -9,7 +9,7 @@ import LoginModal from '../components/LoginModal'
 
 export default function Dashboard({ onLogout }) {
   const navigate = useNavigate()
-  const { user, token, loading: userLoading, isSuperadmin, role } = useUser()
+  const { user, token, loading: userLoading, isSuperadmin, isModerator, role } = useUser()
   const [servers, setServers] = useState([])
   const [displaySettings, setDisplaySettings] = useState({})
   const [loading, setLoading] = useState(true)
@@ -259,6 +259,9 @@ export default function Dashboard({ onLogout }) {
                   isAuthenticated={isAuthenticated}
                   isGuest={isGuest}
                   displaySettings={displaySettings[server.id]}
+                  isModerator={isModerator}
+                  token={token}
+                  onServerAction={fetchServers}
                 />
               </div>
             ))}