fix ts errors

frontend/src/pages/DrawingPadApp.tsx

@@ -122,9 +122,8 @@ export function DrawingPadApp() {
   }, []);
 
   // Set canvas size on mount and resize
-  const canvasRefCallback = useCallback((canvas: HTMLCanvasElement | null) => {
-    canvasRef.current = canvas;
-    if (canvas) {
+  useEffect(() => {
+    if (canvasRef.current) {
       setupCanvas();
     }
   }, [setupCanvas]);
@@ -223,7 +222,7 @@ export function DrawingPadApp() {
 
         <div className="bg-white border-2 border-gray-300 rounded-lg overflow-hidden">
           <canvas
-            ref={canvasRefCallback}
+            ref={canvasRef}
             className={`w-full h-[600px] touch-none ${
               isEraser ? 'cursor-grab' : 'cursor-crosshair'
             }`}

frontend/src/services/apiClient.ts

@@ -6,15 +6,6 @@ const api = axios.create({
   headers: { 'Content-Type': 'application/json' }
 });
 
-// Helper to create API instance without default JSON header (for FormData)
-const createFormDataApi = () => {
-  return axios.create({
-    baseURL: import.meta.env.VITE_API_URL || 'http://localhost:8080/api',
-    withCredentials: true
-    // No default Content-Type - let axios set it automatically for FormData
-  });
-};
-
 let isRefreshing = false;
 let failedQueue: any[] = [];
 
@@ -186,7 +177,7 @@ export const settingsProfilesApi = {
   
   getById: (id: number) => api.get(`/settings-profiles/${id}`),
   
-  create: (data: { name: string; description?: string; dailyTimeLimit: number; enabledApps?: string[] }) =>
+  create: (data: { name: string; description?: string; dailyTimeLimit?: number; enabledApps?: string[] }) =>
     api.post('/settings-profiles', data),
   
   update: (id: number, data: { name?: string; description?: string; isActive?: boolean }) =>