feat: implement project launch script run.sh and update README

frontend/src/pages/Settings.svelte

@@ -133,6 +133,13 @@ None
 
     <section class="mb-8 bg-white p-6 rounded shadow">
         <h2 class="text-xl font-semibold mb-4">Superset Environments</h2>
+
+        {#if settings.environments.length === 0}
+            <div class="mb-4 p-4 bg-yellow-100 border-l-4 border-yellow-500 text-yellow-700">
+                <p class="font-bold">Warning</p>
+                <p>No Superset environments configured. You must add at least one environment to perform backups or migrations.</p>
+            </div>
+        {/if}
         
         <div class="mb-6 overflow-x-auto">
             <table class="min-w-full divide-y divide-gray-200">