Changes back-end unavailable to redirect to login instead of setup page

frontend/src/mocks/index.ts

@@ -9,7 +9,7 @@ export const handlers = [...authHandlers, ...userHandlers, ...setupHandlers, ...
 
 export { authHandlers } from './auth/handlers';
 export { userHandlers } from './users/handlers';
-export { setupHandlers, setupUninitializedHandlers, setupConflictHandlers } from './setup/handlers';
+export { setupHandlers, setupUninitializedHandlers, setupConflictHandlers, setupNetworkErrorHandlers } from './setup/handlers';
 export { invitationHandlers } from './invitation/handlers';
 export { availabilityHandlers } from './availability/handlers';
 export * from './auth/fixtures';

frontend/src/mocks/setup/handlers.ts

@@ -37,6 +37,11 @@ export const setupHandlers = [
     }),
 ];
 
+/** Override: simulates network error on setup status — backend unreachable. */
+export const setupNetworkErrorHandlers = [
+    http.get(`${API_BASE}/api/v1/Setup/status`, () => HttpResponse.error()),
+];
+
 /** Override: returns not-initialized status — use in tests for InitGuard. */
 export const setupUninitializedHandlers = [
     http.get(`${API_BASE}/api/v1/Setup/status`, () =>

frontend/src/router.tsx

@@ -8,7 +8,7 @@ import {
 } from '@tanstack/react-router';
 import type { AuthContextValue } from '@/contexts/auth-context';
 import type { SetupStatus } from '@/api/types';
-import { api } from '@/lib/api-client';
+import { api, NetworkError } from '@/lib/api-client';
 import { AppLayout } from '@/components/layout/AppLayout';
 import { LoginPage } from '@/pages/LoginPage';
 import { NotFoundPage } from '@/pages/NotFoundPage';
@@ -99,10 +99,13 @@ const rootRoute = createRootRouteWithContext<RouterContext>()({
         try {
             status = await fetchSetupStatus();
         } catch (err) {
-            // On network failure, assume not initialized so the user can set up
+            if (err instanceof NetworkError) {
-            // the system once the backend is reachable. Logging helps debugging.
+                // Backend unreachable: skip setup redirect and show the login page instead.
-            console.warn('[InitGuard] Setup status check failed, assuming not initialized:', err);
+                status = { initialized: true };
-            status = { initialized: false };
+            } else {
+                console.warn('[InitGuard] Setup status check failed, assuming not initialized:', err);
+                status = { initialized: false };
+            }
         }
 
         const onSetup = location.pathname === '/setup';

frontend/src/test/RouteGuard.test.tsx

@@ -2,7 +2,7 @@ import { beforeEach, describe, expect, it } from 'vitest';
 import { screen } from '@testing-library/react';
 import { renderApp, mockAuthenticated, mockGuest } from '@/test/utils';
 import { server } from '@/mocks/server';
-import { setupUninitializedHandlers } from '@/mocks/index';
+import { setupUninitializedHandlers, setupNetworkErrorHandlers } from '@/mocks/index';
 import { _resetSetupStatusCache } from '@/router';
 
 beforeEach(() => {
@@ -53,6 +53,24 @@ describe('InitGuard (BR-U2-09, BR-U2-10)', () => {
         expect(await screen.findByTestId('setup-submit-button')).toBeInTheDocument();
     });
 
+    it('shows login page (not setup) when backend is unreachable', async () => {
+        server.use(...setupNetworkErrorHandlers);
+        mockGuest();
+        renderApp('/login');
+
+        expect(await screen.findByTestId('login-form-submit-button')).toBeInTheDocument();
+        expect(screen.queryByTestId('setup-submit-button')).not.toBeInTheDocument();
+    });
+
+    it('redirects /setup to /login when backend is unreachable', async () => {
+        server.use(...setupNetworkErrorHandlers);
+        mockGuest();
+        renderApp('/setup');
+
+        expect(await screen.findByTestId('login-form-submit-button')).toBeInTheDocument();
+        expect(screen.queryByTestId('setup-submit-button')).not.toBeInTheDocument();
+    });
+
     it('redirects /setup to /login when system is already initialized', async () => {
         // Default handlers return { initialized: true }.
         mockGuest();