Access permissions, seed permissions, security, session, api/session improved handling + speed across the site/UX improvements

frontend/src/routes/scenarios/+page.svelte

@@ -11,14 +11,6 @@
   const approvedCount = $derived(scenarioRows.filter((scenario) => scenario.status === 'approved').length);
 </script>
 
-<section class="page-intro">
-  <div>
-    <p class="eyebrow">Scenario Sandbox</p>
-    <h2>Simulation workspaces with a cleaner review and comparison layer.</h2>
-    <p>Scenarios now read like structured operating plans instead of raw debug output.</p>
-  </div>
-</section>
-
 <section class="metric-row">
   <article class="metric-card">
     <span>Total Scenarios</span>