feat(audit): undo button for merges, hide manual games

The audit log shows Undo on a merge row for 30 days, with a confirm
dialog and clear errors. The details page follows a merged key to the
kept game. Hide and Show now work for manual games too. de/en texts.

src/pages/AuditLogPage.jsx

@@ -1,17 +1,18 @@
 import {useCallback, useEffect, useState} from 'react';
 import {Link} from 'react-router-dom';
 import {useTranslation} from 'react-i18next';
-import {ChevronLeft, ChevronRight, Loader2} from 'lucide-react';
+import {ChevronLeft, ChevronRight, Loader2, Undo2} from 'lucide-react';
 
 import {Button} from '@/components/ui/button';
 import {Card, CardContent, CardHeader, CardTitle} from '@/components/ui/card';
 import {Select, SelectContent, SelectItem, SelectTrigger, SelectValue} from '@/components/ui/select';
 import PageContainer from '../components/PageContainer.jsx';
-import {fetchAuditLog} from '../utils/links.js';
+import {toast} from 'sonner';
+import {fetchAuditLog, undoMerge} from '../utils/links.js';
 import {formatDateTime} from '../utils/format.js';
 
 const PAGE_SIZE = 20;
-const ACTIONS = ['GAME_MERGE', 'GAME_LINK', 'GAME_UNLINK', 'GAME_LINK_DISMISS', 'GAME_CORRECT',
+const ACTIONS = ['GAME_MERGE', 'GAME_MERGE_UNDO', 'GAME_LINK', 'GAME_UNLINK', 'GAME_LINK_DISMISS', 'GAME_CORRECT',
     'GAME_CORRECTION_RESET'];
 const ALL = 'ALL';
 
@@ -29,6 +30,7 @@ export default function AuditLogPage() {
     const [page, setPage] = useState(0);
     const [result, setResult] = useState({content: [], totalPages: 0});
     const [status, setStatus] = useState('loading');
+    const [undoing, setUndoing] = useState(false);
 
     const load = useCallback(async () => {
         try {
@@ -54,6 +56,30 @@ export default function AuditLogPage() {
         load();
     }, [load]);
 
+    const onUndo = async (entry) => {
+        // The merged key has no catalog row any more; its name is the first one in the detail.
+        const name = entry.gameName ?? /^"(.*?)" into "/.exec(entry.detail ?? '')?.[1] ?? entry.appid;
+        const other = entry.targetGameName ?? entry.targetAppid;
+        if (!window.confirm(t('AUDIT.UNDO.CONFIRM', {name, other}))) return;
+        setUndoing(true);
+        try {
+            const response = await undoMerge(entry.id);
+            if (response.status === 401) return;
+            if (response.ok) {
+                toast.success(t('AUDIT.UNDO.DONE'));
+            } else {
+                const data = await response.json().catch(() => ({}));
+                toast.error(t(`AUDIT.UNDO.ERROR_CODES.${data.code}`, {defaultValue: t('AUDIT.UNDO.ERROR')}));
+            }
+            await load();
+        } catch (err) {
+            console.error('Undo merge error:', err);
+            toast.error(t('INFO.ERROR.NETWORK_FAILURE'));
+        } finally {
+            setUndoing(false);
+        }
+    };
+
     const onActionChange = (value) => {
         setAction(value);
         setPage(0);
@@ -100,6 +126,12 @@ export default function AuditLogPage() {
                                         <GameRef appid={entry.targetAppid} name={entry.targetGameName} fallback={entry.targetAppid}/>
                                     </p>
                                     {entry.detail && <p className="break-words text-xs text-muted-foreground">{entry.detail}</p>}
+                                    {entry.action === 'GAME_MERGE' && entry.undoable && (
+                                        <Button type="button" variant="outline" size="sm" disabled={undoing}
+                                                onClick={() => onUndo(entry)}>
+                                            <Undo2/>{t('AUDIT.UNDO.BUTTON')}
+                                        </Button>
+                                    )}
                                 </li>
                             ))}
                         </ul>