Confirmation overlay for installing a model provider's extra.
Shown from the model selector when the user picks a model whose provider
integration package is not installed. Dismisses with True to install and
False to cancel; Esc cancels so the user is never forced into an install.
The provider whose integration is missing.
The deepagents-code extra that installs the provider.
The selected provider:model spec, surfaced in the body
by the model selector. Omitted by the /auth manager, which
installs a provider so a key can be added rather than to switch
to a specific model.
Compose the provider-install confirmation dialog.
Dismiss with True.
Dismiss with False.
The method name must stay cancel for the same reason as
InstallPackageConfirmScreen.action_cancel: the app's priority
escape binding dispatches to it for an active ModalScreen.
