Add favorite cards display on homepage

- Fetch and display users' favorite cards at the top of homepage
- Filter users with fav \!== '0' to avoid empty display
- Use useQueries to fetch multiple users' cards in parallel
- Display cards in grid layout with owner username below
- Cards are shown above the user list section

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/utils/api.ts

@@ -52,6 +52,16 @@ export const fetchUserCards = async (userId: number, itemsPerPage = 8000): Promi
   }
 };
 
+export const fetchCardById = async (cardId: number): Promise<Card | null> => {
+  try {
+    const response = await api.get(`cards/${cardId}`);
+    return response.data;
+  } catch (error) {
+    console.error('Failed to fetch card by ID:', error);
+    return null;
+  }
+};
+
 export const fetchUser = async (userId: number): Promise<{ data: User }> => {
   const response = await api.get(`users/${userId}`);
   return response.data;