Promote to UAT: GRO-2094 React bootstrap error instrumentation (#45)

Co-authored-by: The Dogfather <20+gb_dogfather@noreply.git.farh.net>
Co-committed-by: The Dogfather <20+gb_dogfather@noreply.git.farh.net>

src/App.tsx

@@ -378,8 +378,12 @@ export function App() {
     return <Navigate to="/login" replace />;
   }
 
-  // Show login BEFORE checking needsSetup (needsSetup is never set for unauthenticated users)
-  if (!authDisabled && !session) {
+  // Show login BEFORE checking needsSetup (needsSetup is never set for unauthenticated users).
+  // At /login with a valid session, fall through so the staff redirect below can
+  // route staff to /admin and the final render can redirect customers to / (portal).
+  // Previously, an authenticated customer at /login would see a blank page because
+  // the final render returns null at /login (showCustomerPortal is false). See GRO-2099.
+  if (!authDisabled && !session && location.pathname === "/login") {
     return <LoginPage />;
   }
 
@@ -401,6 +405,14 @@ export function App() {
   // Don't render portal chrome at /login — DevLoginSelector is shown instead
   const showCustomerPortal = !location.pathname.startsWith("/admin") && location.pathname !== "/login";
 
+  // At /login with a valid session, redirect to the portal root. Without this,
+  // the final render returns null at /login (showCustomerPortal is false) and
+  // the user sees a blank page after a successful sign-in. Staff are routed
+  // to /admin by the earlier staff check. See GRO-2099.
+  if (!authDisabled && session && location.pathname === "/login") {
+    return <Navigate to="/" replace />;
+  }
+
   return (
     <BrandingProvider>
       {location.pathname.startsWith("/admin") ? (