fix(ui): make pagination labels always visible to screenreader

- The pagination labels 'First', 'Previous', 'Next' and 'Last' are
hidden away when the screen width becomes smaller. However this also
hides them from the screen reader. Instead of using `display: none`, use
some well-known tricks to still make them visible to the screen reader.
- Add E2E test.
- Resolves Codeberg/Community#1858

tests/e2e/pagination.test.e2e.ts

@@ -0,0 +1,15 @@
+// @watch start
+// template/base/paginate.tmpl
+// services/context/pagination.go
+// @watch end
+
+import {expect} from '@playwright/test';
+import {test} from './utils_e2e.ts';
+import {accessibilityCheck} from './shared/accessibility.ts';
+
+test('Pagination a11y', async ({page}) => {
+  await page.goto('/explore/repos');
+
+  await expect(page.locator('.pagination')).toBeVisible();
+  await accessibilityCheck({page}, ['.pagination'], [], []);
+});

web_src/css/base.css

@@ -952,7 +952,15 @@ img.ui.avatar,
 @media (max-width: 767.98px) {
   .ui.pagination.menu .item:not(.active,.navigation),
   .ui.pagination.menu .item.navigation span.navigation_label {
-    display: none;
+    position: absolute;
+    width: 1px;
+    height: 1px;
+    padding: 0;
+    margin: -1px;
+    overflow: hidden;
+    clip: rect(0, 0, 0, 0);
+    white-space: nowrap;
+    border-width: 0;
   }
 }