Toaster

Two live regions, in the document before any message arrives.

**This is the detail that decides whether a message is read out at all.** Add
the live region and the text at the same time and a screen reader never
notices the change, so nothing is announced. Both regions are therefore always
rendered, empty or not.

Two regions, not one: confirmations are `polite` so they do not interrupt,
errors are `assertive` so they do. `toast.error` stays until dismissed by
default, because a message you have to read should not disappear while you are
reading it.

In an Inertia app use `Flash` instead — it renders the Toaster and turns
Askr's flash into toasts, carrying whatever keys your app sets:

```pascal
InertiaFlash('success', 'Customer ' + C.Name + ' was created.');
```
```svelte
<Flash />   <!-- once, in your layout -->
```