feat(desktop): optional wipe-on-close (Settings -> Sicherheit)

apps/desktop/src/context/AuthContext.tsx

@@ -21,6 +21,7 @@ import { useTranslation } from 'react-i18next';
 
 import { ensureInstallId } from '../lib/installId';
 import { wipeLocalState } from '../lib/memoryWipe';
+import { isWipeOnCloseEnabled } from '../lib/memoryWipeSettings';
 import { setSecretStoreUser } from '../lib/secretStore';
 import { supabase } from '../lib/supabase';
 import { cachedUserKey, ensureLegacyMigrated } from '../lib/userIdentity';
@@ -195,6 +196,18 @@ export function AuthProvider({ children }: { children: ReactNode }) {
     void registerWebPush(installId);
   }, [session]);
 
+  // Wipe-on-close: register a handler the main process pings on `before-quit`
+  // when the user has enabled the Settings → Sicherheit toggle. No-op outside
+  // Electron (web build has no preload bridge) or when the toggle is off.
+  useEffect(() => {
+    if (typeof window.electronAPI?.onWipeBeforeQuit !== 'function') return;
+    const unsub = window.electronAPI.onWipeBeforeQuit(async () => {
+      if (!isWipeOnCloseEnabled()) return;
+      await wipeLocalState(session?.user.id ?? null);
+    });
+    return unsub;
+  }, [session?.user.id]);
+
   // Auto online/offline transition.
   //
   // - On mount with a session whose last persisted state is `offline`, flip