feat: render flash messages as toasts

Co-Authored-By: Claude Opus 5 <[email protected]>

importmap.php

@@ -25,4 +25,11 @@ return [
     'htmx.org' => [
         'version' => '2.0.10',
     ],
+    'toastify-js' => [
+        'version' => '1.12.0',
+    ],
+    'toastify-js/src/toastify.css' => [
+        'version' => '1.12.0',
+        'type' => 'css',
+    ],
 ];