Function create_app 

pub async fn create_app(
    environment: &Environment,
    app_id: &str,
    app_secret: &str,
    access_token: &str,
    name: &str,
) -> Result<OndeApp, GresiqError>

Create a new app under the authenticated user’s account.

POST /v1/client/gresiq/apps — body: { "gresiq_app": { "name": "..." } }