fix: remove dead /server/ fallback redirect

When no org is resolved, redirect to /tenant instead of the
non-existent /server/ path. Fixes login redirect loop.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/router.tsx

@@ -39,9 +39,12 @@ function LandingRedirect() {
     return <Navigate to="/tenant" replace />;
   }
   // Regular user (operator/viewer) → server dashboard directly
-  const serverUrl = currentOrg?.slug ? `/t/${currentOrg.slug}/` : '/server/';
-  window.location.href = serverUrl;
-  return null;
+  if (currentOrg?.slug) {
+    window.location.href = `/t/${currentOrg.slug}/`;
+    return null;
+  }
+  // No org resolved yet — stay on tenant portal
+  return <Navigate to="/tenant" replace />;
 }
 
 export function AppRouter() {