Create conversation assignment

curl --request POST \
  --url https://api.kapso.ai/platform/v1/whatsapp/conversations/{conversation_id}/assignments \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "assignment": {
    "user_id": "f1e2d3c4-b5a6-9870-fedc-ba0987654321",
    "notes": "Customer needs help with integration"
  }
}
'

{
  "data": {
    "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "user_id": "f1e2d3c4-b5a6-9870-fedc-ba0987654321",
    "created_by_user_id": "f1e2d3c4-b5a6-9870-fedc-ba0987654321",
    "notes": "Customer needs help with integration",
    "active": true,
    "created_at": "2026-01-19T10:30:00Z"
  }
}