catch all 404 errors, that haven't been handled

src/routes/[...catchall]/+page.svelte

@@ -0,0 +1,14 @@
+<script lang="ts">
+  import { page } from '$app/stores';
+  import { goto } from '$app/navigation';
+  import { Button, P } from 'flowbite-svelte';
+</script>
+
+<div class="flex flex-col items-center justify-center min-h-screen text-center px-4">
+  <h1 class="text-4xl font-bold mb-4">404 - Page Not Found</h1>
+  <P class="mb-6">The page you are looking for does not exist or has been moved.</P>
+  <div class="flex space-x-4">
+    <Button class="btn-leather" on:click={() => goto('/')}>Return to Home</Button>
+    <Button class="btn-leather" outline on:click={() => window.history.back()}>Go Back</Button>
+  </div>
+</div>