feat(stats): add stats page and pile trend

Show the stat groups on /stats, the pile trend on the dashboard card,
one switch per group in the settings, and the shared groups on the
public profile.

src/pages/SettingsPage.test.jsx

@@ -55,6 +55,57 @@ describe('SettingsPage public profile', () => {
         await waitFor(() => expect(screen.queryByText(/\/u\/Lobo$/)).toBeNull());
     });
 
+    it('saves the stat groups the public profile shows, in a fixed order', async () => {
+        renderPage(profile({settings: {useDarkTheme: true, language: 'de', publicProfile: true, profileStats: ['TREND']}}));
+
+        fireEvent.click(await screen.findByRole('switch', {name: 'STATS.PILE.TITLE'}));
+
+        await waitFor(() => expect(puts()).toHaveLength(1));
+        expect(puts()[0]).toEqual({groups: ['PILE', 'TREND']});
+        const [url] = fetch.mock.calls.find(([, init]) => init?.method === 'PUT');
+        expect(url).toMatch(/\/api\/users\/settings\/profile-stats$/);
+        await waitFor(() => expect(screen.getByRole('switch', {name: 'STATS.PILE.TITLE'}).getAttribute('aria-checked'))
+            .toBe('true'));
+    });
+
+    it('waits for a save before the next switch click', async () => {
+        const answers = [];
+        const me = profile({settings: {useDarkTheme: true, language: 'de', publicProfile: true, profileStats: []}});
+        globalThis.fetch = vi.fn((url, init) => (init?.method === 'PUT'
+            ? new Promise((resolve) => answers.push(() => resolve({ok: true, status: 204, json: async () => ({})})))
+            : Promise.resolve({ok: true, status: 200, json: async () => me})));
+        render(<MemoryRouter><PreferencesProvider><SettingsPage/></PreferencesProvider></MemoryRouter>);
+
+        fireEvent.click(await screen.findByRole('switch', {name: 'STATS.PILE.TITLE'}));
+        await waitFor(() => expect(screen.getByRole('switch', {name: 'STATS.TASTE.TITLE'}).disabled).toBe(true));
+        answers.forEach((answer) => answer());
+        await waitFor(() => expect(screen.getByRole('switch', {name: 'STATS.TASTE.TITLE'}).disabled).toBe(false));
+        fireEvent.click(screen.getByRole('switch', {name: 'STATS.TASTE.TITLE'}));
+
+        await waitFor(() => expect(puts()).toHaveLength(2));
+        expect(puts()[1]).toEqual({groups: ['PILE', 'TASTE']});
+    });
+
+    it('switches the group back when the save fails', async () => {
+        const me = profile({settings: {useDarkTheme: true, language: 'de', publicProfile: true, profileStats: []}});
+        globalThis.fetch = vi.fn(async (url, init) => (init?.method === 'PUT'
+            ? {ok: false, status: 500, json: async () => ({})}
+            : {ok: true, status: 200, json: async () => me}));
+        render(<MemoryRouter><PreferencesProvider><SettingsPage/></PreferencesProvider></MemoryRouter>);
+
+        fireEvent.click(await screen.findByRole('switch', {name: 'STATS.PILE.TITLE'}));
+
+        await waitFor(() => expect(screen.getByRole('switch', {name: 'STATS.PILE.TITLE'}).getAttribute('aria-checked'))
+            .toBe('false'));
+    });
+
+    it('offers the stat groups only while the profile is public', async () => {
+        renderPage(profile({settings: {useDarkTheme: true, language: 'de', publicProfile: false}}));
+
+        expect((await screen.findByRole('switch', {name: 'STATS.PILE.TITLE'})).disabled).toBe(true);
+        expect(screen.getByText('SETTINGS.PROFILE_STATS_NEEDS_PUBLIC')).toBeTruthy();
+    });
+
     it('needs a display name first', async () => {
         renderPage(profile({displayName: null, settings: {useDarkTheme: true, language: 'de', publicProfile: false}}));