refactor(ImageLightbox): pin close button via a fixed wrapper

src/shared/ui/ImageLightbox/ui/ImageLightbox.test.tsx

@@ -81,10 +81,10 @@ describe('ImageLightbox', () => {
       expect(document.body.style.overflow).toBe('');
     });
 
-    it('close button is positioned fixed', () => {
+    it('close button is pinned via a fixed wrapper', () => {
       render(<ImageLightbox {...DEFAULT_PROPS} />);
       const closeBtn = screen.getByRole('button', { name: /close/i, hidden: true });
-      expect(closeBtn).toHaveClass('fixed');
+      expect(closeBtn.parentElement).toHaveClass('fixed');
     });
   });
 });

src/shared/ui/ImageLightbox/ui/ImageLightbox.tsx

@@ -188,9 +188,11 @@ export function ImageLightbox({
             className="lightbox-image block w-auto h-auto"
           />
         </div>
-        <Button variant="outline" size="sm" onClick={close} aria-label="Close image" className="fixed top-3 right-3">
+        <div className="fixed top-3 right-3">
+          <Button variant="outline" size="sm" onClick={close} aria-label="Close image">
             <CloseIcon />
           </Button>
+        </div>
       </Modal>
     </>
   );