curl --request POST \
  --url https://api.wacht.dev/organizations/invitations/accept \
  --header 'Content-Type: application/x-www-form-urlencoded' \
  --cookie session_id= \
  --data token=inv_token_abc123

{
  "organization": {
    "id": "<string>",
    "name": "<string>"
  },
  "workspace": {
    "id": "<string>",
    "name": "<string>"
  },
  "signin_id": "555555555555555555",
  "already_member": false,
  "message": "Invitation accepted",
  "requires_signin": false,
  "invited_email": "user@example.com",
  "error_code": "<string>"
}