Post base collaborator

curl --request POST \
  --url http://127.0.0.1:3000/api/base/{baseId}/collaborator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "collaborators": [
    {
      "principalId": "<string>",
      "principalType": "user"
    }
  ],
  "role": "creator"
}
'