Create subscription button now visible on an empty subscription list

On the Subscriptions list page, the primary Create subscription button only appeared when the merchant already had at least one subscription contract. A store with zero contracts saw neither the button nor any admin-side path to create one manually. The only option in the empty state was a storefront-facing link.

This is fixed. The Create subscription button now appears in the page header regardless of how many contracts exist, so staff can create a subscription manually for a customer at any time.