feat: update loading skeleton and playlist handling for main playlists

src/components/playlists/playlist-edit/PlaylistDetailsCard.tsx

@@ -117,7 +117,13 @@ export function PlaylistDetailsCard({
 
         {/* Edit/Save/Cancel buttons */}
         <div className="pt-4 border-t">
-          {isEditMode ? (
+          {playlist.is_main ? (
+            <div className="text-center">
+              <p className="text-sm text-muted-foreground">
+                Main playlist details cannot be edited
+              </p>
+            </div>
+          ) : isEditMode ? (
             <div className="flex justify-end gap-2">
               <Button variant="outline" onClick={onCancelEdit}>
                 <X className="h-4 w-4 mr-2" />