curl -X POST "https://server.smartlead.ai/api/v1/lead-list/assign-tags?api_key=YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"listIds": [500, 501], "tagIds": [1, 2], "removeTagIds": [3]}'

{
  "ok": true,
  "message": "Tags updated successfully"
}

{
  "message": "Invalid API Key"
}