refactor(web): pushToast store + ToastHost; 8 sites migrated (W3)

web/src/routes/+layout.svelte

@@ -7,6 +7,7 @@
   import { user } from '$lib/auth/store.svelte';
   import Shell from '$lib/components/Shell.svelte';
   import QueueDrawer from '$lib/components/QueueDrawer.svelte';
+  import ToastHost from '$lib/components/ToastHost.svelte';
   import {
     registerAudioEl,
     reportTimeUpdate,
@@ -111,3 +112,5 @@
     {@render children()}
   {/if}
 </QueryClientProvider>
+
+<ToastHost />