feat(hint): targets, automatic hints and formatting

Target fields on the admin hints page. The dashboard shows the four
automatic hints after admin hints when their condition is true, using
data Core already serves. HintText renders **bold** and safe links (app
path or https) as React elements, never HTML, in hints and news.
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src/pages/AdminHintsPage.test.jsx

@@ -17,9 +17,11 @@ const ACTIVE = {id: 2, textEn: 'Server update tonight', textDe: null, kind: 'DIS
 const ENDED = {...ACTIVE, id: 1, textEn: 'Old news', startsAt: at(-3), endsAt: at(-2), status: 'ENDED', doneCount: 0};
 
 const withRoutes = (routes) => fetchRoutes({
-    'GET /api/admin/hints': json(200, {results: [ACTIVE, ENDED]}),
+    'GET /api/admin/hints': json(200, {results: [ACTIVE, ENDED],
+        automatic: [{key: 'NO_STEAM', enabled: true}, {key: 'PILE_GREW', enabled: true}]}),
     'POST /api/admin/hints': json(201, {id: 3}),
     'PUT /api/admin/hints/2/end': json(204),
+    'PUT /api/admin/hints/auto/PILE_GREW': json(204),
     ...routes,
 });
 const calls = (method) => fetch.mock.calls.filter(([, init]) => (init?.method ?? 'GET') === method);
@@ -69,6 +71,53 @@ describe('AdminHintsPage', () => {
         expect(screen.getByLabelText('ADMIN_HINTS.TEXT_EN').value).toBe('');
     });
 
+    it('sends the target groups, empty ones as null', async () => {
+        renderPage();
+        await screen.findByText('Server update tonight');
+
+        fireEvent.change(screen.getByLabelText('ADMIN_HINTS.TEXT_EN'), {target: {value: 'News'}});
+        fireEvent.click(screen.getByLabelText('ADMIN_HINTS.TARGET_NO_STEAM'));
+        fireEvent.change(screen.getByLabelText('ADMIN_HINTS.TARGET_NEW_DAYS'), {target: {value: '7'}});
+        fireEvent.change(screen.getByLabelText('ADMIN_HINTS.TARGET_ROLE'), {target: {value: 'AUDITOR'}});
+        fireEvent.click(screen.getByText('ADMIN_HINTS.CREATE'));
+        await waitFor(() => expect(calls('POST')).toHaveLength(1));
+        expect(JSON.parse(calls('POST')[0][1].body)).toMatchObject({
+            targetNoSteam: true, targetRole: 'AUDITOR', targetNewDays: 7, targetEmptyLibrary: false});
+        await waitFor(() => expect(toast.success).toHaveBeenCalledWith('ADMIN_HINTS.CREATED'));
+
+        fireEvent.change(screen.getByLabelText('ADMIN_HINTS.TEXT_EN'), {target: {value: 'More news'}});
+        fireEvent.click(screen.getByText('ADMIN_HINTS.CREATE'));
+        await waitFor(() => expect(calls('POST')).toHaveLength(2));
+        expect(JSON.parse(calls('POST')[1][1].body)).toMatchObject({
+            targetNoSteam: false, targetRole: null, targetNewDays: null, targetEmptyLibrary: false});
+    });
+
+    it('shows the role labels for the role target', async () => {
+        renderPage();
+        expect(await screen.findByRole('option', {name: 'ROLES.AUDITOR'})).toBeTruthy();
+    });
+
+    it('turns an automatic hint off', async () => {
+        renderPage();
+        await screen.findByText('Server update tonight');
+
+        fireEvent.click(screen.getByLabelText('ADMIN_HINTS.AUTO_PILE_GREW'));
+
+        await waitFor(() => expect(toast.success).toHaveBeenCalledWith('ADMIN_HINTS.AUTO_SAVED'));
+        const [url, init] = calls('PUT')[0];
+        expect(url).toContain('/api/admin/hints/auto/PILE_GREW');
+        expect(JSON.parse(init.body)).toEqual({enabled: false});
+    });
+
+    it('previews bold text', async () => {
+        renderPage();
+        await screen.findByText('Server update tonight');
+
+        fireEvent.change(screen.getByLabelText('ADMIN_HINTS.TEXT_EN'), {target: {value: 'Read **this**'}});
+
+        expect(document.querySelector('[role="status"] strong').textContent).toBe('this');
+    });
+
     it('explains an invalid time range', async () => {
         withRoutes({'GET /api/admin/hints': json(200, {results: []}), 'POST /api/admin/hints': json(400, {code: 'INVALID_HINT'})});
         renderPage();