🔧 Fix TypeScript test errors

- Fixed response.init.status → response.status
- Fixed response.init.headers → response.headers.get()
- All TypeScript type checks now pass ✅

app/__tests__/api/fetchImage.test.tsx

@@ -37,7 +37,7 @@ describe('GET /api/fetchImage', () => {
     const response = await GET(mockRequest);
 
     expect(response.body).toEqual({ error: 'Missing URL parameter' });
-    expect(response.init.status).toBe(400);
+    expect(response.status).toBe(400);
   });
 
   it('should fetch an image if URL is provided', async () => {
@@ -48,6 +48,6 @@ describe('GET /api/fetchImage', () => {
     const response = await GET(mockRequest);
 
     expect(response.body).toBeDefined();
-    expect(response.init.headers['Content-Type']).toBe('image/jpeg');
+    expect(response.headers.get('Content-Type')).toBe('image/jpeg');
   });
 });