feat(questions): list and restore removed games

Add a "Removed games" section on the questions page and an Undo
toast after removing a manual game (#39).

src/components/RemovedGamesSection.jsx

@@ -0,0 +1,70 @@
+import {useEffect, useState} from 'react';
+import {useTranslation} from 'react-i18next';
+import {toast} from 'sonner';
+
+import {Button} from '@/components/ui/button';
+import GameCover from './GameCover.jsx';
+import {fetchRemovedGames, restoreGame} from '../utils/manualGames.js';
+
+/**
+ * The games the user removed, in a closed `<details>`, one Restore button each. Shows nothing when there are none or
+ * the list does not load: it is a safety net, not a page.
+ */
+export default function RemovedGamesSection() {
+    const {t} = useTranslation();
+    const [games, setGames] = useState([]);
+    const [busy, setBusy] = useState(false);
+
+    useEffect(() => {
+        let active = true;
+        fetchRemovedGames().then(({ok, data}) => {
+            if (active && ok) setGames(data.results);
+        });
+        return () => {
+            active = false;
+        };
+    }, []);
+
+    const restore = async (appid) => {
+        setBusy(true);
+        try {
+            const response = await restoreGame(appid);
+            if (response.status === 401) return;
+            if (response.ok || response.status === 404) {
+                setGames((current) => current.filter((game) => game.appid !== appid));
+                if (response.ok) toast.success(t('REMOVED_GAMES.RESTORED'));
+            } else {
+                toast.error(t('BACKLOG.SAVE_FAILED'));
+            }
+        } catch (err) {
+            console.error('restore error:', err);
+            toast.error(t('INFO.ERROR.NETWORK_FAILURE'));
+        } finally {
+            setBusy(false);
+        }
+    };
+
+    if (games.length === 0) return null;
+    return (
+        <details className="rounded-lg border p-4">
+            <summary className="cursor-pointer font-medium">{t('REMOVED_GAMES.TITLE_COUNT', {count: games.length})}</summary>
+            <p className="mt-3 text-sm text-muted-foreground">{t('REMOVED_GAMES.HINT')}</p>
+            <ul className="mt-3 space-y-3">
+                {games.map((game) => (
+                    <li key={game.appid} className="flex items-center gap-3">
+                        <div className="w-16 shrink-0">
+                            <GameCover appid={game.appid} imageUrl={game.imageUrl}/>
+                        </div>
+                        <div className="min-w-0 flex-1">
+                            <p className="truncate font-medium">{game.name ?? `App ${game.appid}`}</p>
+                            {game.platform && <p className="text-sm text-muted-foreground">{game.platform}</p>}
+                        </div>
+                        <Button type="button" size="sm" variant="outline" disabled={busy} onClick={() => restore(game.appid)}>
+                            {t('REMOVED_GAMES.RESTORE')}
+                        </Button>
+                    </li>
+                ))}
+            </ul>
+        </details>
+    );
+}