refactor(frontend): lint, one session guard, one request helper, one user context

src/hooks/useSaveAppearance.test.jsx

@@ -1,17 +1,21 @@
 // @vitest-environment jsdom
 import {afterEach, beforeEach, describe, expect, it, vi} from 'vitest';
 import {act, cleanup, renderHook} from '@testing-library/react';
-import {MemoryRouter} from 'react-router-dom';
+import {MemoryRouter, Route, Routes} from 'react-router-dom';
 import {toast} from 'sonner';
 import {PreferencesProvider, usePreferences} from '../context/PreferencesContext.jsx';
 import useSaveAppearance from './useSaveAppearance.js';
+import RequireSession from '../components/RequireSession.jsx';
 import {DEFAULT_APPEARANCE} from '../utils/appearance.js';
 
 vi.mock('react-i18next', () => import('../test/i18n-mock.js'));
 vi.mock('sonner', () => ({toast: {success: vi.fn(), error: vi.fn()}}));
 
+// RequireSession ends the session on a 401, as on the pages that use the hook.
 const wrapper = ({children}) => (
-    <MemoryRouter><PreferencesProvider>{children}</PreferencesProvider></MemoryRouter>
+    <MemoryRouter><PreferencesProvider>
+        <Routes><Route element={<RequireSession/>}><Route path="*" element={children}/></Route></Routes>
+    </PreferencesProvider></MemoryRouter>
 );
 
 const renderSave = () => renderHook(() => ({save: useSaveAppearance(), preferences: usePreferences()}), {wrapper});