✨ feat: add loading bar and toast notification system with responsive design

frontend/src/App.svelte

@@ -2,6 +2,8 @@
     import { metricCall } from "./config"
     import { location } from "./lib/store"
     import { _, locale } from "./lib/i18n/index"
+    import LoadingBar from "./widgets/LoadingBar.svelte"
+    import ToastContainer from "./widgets/ToastContainer.svelte"
     import {
         SUPPORTED_LANGUAGES,
         LANGUAGE_LABELS,
@@ -60,6 +62,9 @@
     })
 </script>
 
+<LoadingBar />
+<ToastContainer />
+
 <header class="text-white p-4 bg-red-900">
     <div class="container mx-auto flex flex-wrap items-center justify-between gap-2">
         <a href={localizedPath("/")} class="text-xl font-bold shrink-0">Tibi Svelte Starter</a>