Function dropOnFolder

static/js/catalog.js:793–806

(folderId, trackId)

}

function dropOnFolder(folderId, trackId) {
  const id = trackId ?? dragId;
  if (!id) return;
  // Remove from current folder
  for (const f of folders) {
    const idx = f.items.indexOf(id);
    if (idx !== -1) { f.items.splice(idx, 1); break; }
  }
  // Add to target folder
  const target = folders.find((f) => f.id === folderId);
  if (target && !target.items.includes(id)) target.items.push(id);
  saveState();
  render();
}

function wireTrackDragAndLoad(el, trackId) {
  el.draggable = true;