Create asset collection

curl --request POST \
  --url https://api.fal.ai/v1/assets/collections \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "Campaign concepts"
}
'

{
  "collection": {
    "id": "d8b6elcregj72v34jr8g",
    "type": "manual",
    "name": "Campaign concepts",
    "description": "Reusable campaign imagery",
    "icon": "folder",
    "color": "blue",
    "cover_image_url": "https://v3b.fal.media/files/b/0a9b4900/PDbTGyzqRh1aijW2WQiY9_opengraph-1%20%281%29.png",
    "character_identifier": null,
    "is_favorited": false,
    "filters": null,
    "created_at": "2026-05-23T20:00:00.000Z",
    "updated_at": "2026-05-23T20:00:00.000Z"
  }
}