Adds ability to rename favorite

frontend/src/api/player.tsx

@@ -158,5 +158,15 @@ export const API = {
 
   async clearFavorites(): Promise<void> {
     await fetch('/api/favorites', { method: 'DELETE' });
+  },
+
+  async updateFavoriteTitle(filename: string, title: string): Promise<void> {
+    await fetch(`/api/favorites/${encodeURIComponent(filename)}/title`, {
+      method: 'PUT',
+      headers: {
+        'Content-Type': 'application/json',
+      },
+      body: JSON.stringify({ title }),
+    });
   }
 };