feat: signal when chat runs complete

Users can miss chat completions while the app is in the background.

They can also miss completions when their attention is elsewhere.

Add opt-out sound notifications and a temporary title marker.

This makes completion noticeable without external audio assets or persistent browser notifications.

src/components/chat/hooks/useChatRealtimeHandlers.ts

@@ -2,6 +2,8 @@ import { useEffect, useRef } from 'react';
 import type { Dispatch, MutableRefObject, SetStateAction } from 'react';
 
 import { usePaletteOps } from '../../../contexts/PaletteOpsContext';
+import { showCompletionTitleIndicator } from '../../../utils/pageTitleNotification';
+import { playChatCompletionSound } from '../../../utils/notificationSound';
 import type { PendingPermissionRequest, SessionNavigationOptions } from '../types/types';
 import type { ProjectSession, LLMProvider } from '../../../types/app';
 import type { SessionStore, NormalizedMessage } from '../../../stores/useSessionStore';
@@ -285,6 +287,9 @@ export function useChatRealtimeHandlers({
           break;
         }
 
+        showCompletionTitleIndicator();
+        void playChatCompletionSound();
+
         const actualSessionId =
           typeof msg.actualSessionId === 'string' && msg.actualSessionId.trim().length > 0
             ? msg.actualSessionId

src/components/settings/hooks/useSettingsController.ts

@@ -1,6 +1,8 @@
 import { useCallback, useEffect, useRef, useState } from 'react';
+
 import { useTheme } from '../../../contexts/ThemeContext';
 import { authenticatedFetch } from '../../../utils/api';
+import { setNotificationSoundEnabled } from '../../../utils/notificationSound';
 import { useProviderAuthStatus } from '../../provider-auth/hooks/useProviderAuthStatus';
 import {
   DEFAULT_CODE_EDITOR_SETTINGS,
@@ -107,6 +109,7 @@ const createDefaultNotificationPreferences = (): NotificationPreferencesState =>
   channels: {
     inApp: true,
     webPush: false,
+    sound: true,
   },
   events: {
     actionRequired: true,
@@ -115,6 +118,25 @@ const createDefaultNotificationPreferences = (): NotificationPreferencesState =>
   },
 });
 
+const normalizeNotificationPreferences = (
+  preferences?: Partial<NotificationPreferencesState> | null,
+): NotificationPreferencesState => {
+  const defaults = createDefaultNotificationPreferences();
+
+  return {
+    channels: {
+      inApp: preferences?.channels?.inApp ?? defaults.channels.inApp,
+      webPush: preferences?.channels?.webPush ?? defaults.channels.webPush,
+      sound: preferences?.channels?.sound ?? defaults.channels.sound,
+    },
+    events: {
+      actionRequired: preferences?.events?.actionRequired ?? defaults.events.actionRequired,
+      stop: preferences?.events?.stop ?? defaults.events.stop,
+      error: preferences?.events?.error ?? defaults.events.error,
+    },
+  };
+};
+
 export function useSettingsController({ isOpen, initialTab }: UseSettingsControllerArgs) {
   const { isDarkMode, toggleDarkMode } = useTheme() as ThemeContextValue;
   const closeTimerRef = useRef<number | null>(null);
@@ -186,7 +208,7 @@ export function useSettingsController({ isOpen, initialTab }: UseSettingsControl
         if (notificationResponse.ok) {
           const notificationData = await toResponseJson<NotificationPreferencesResponse>(notificationResponse);
           if (notificationData.success && notificationData.preferences) {
-            setNotificationPreferences(notificationData.preferences);
+            setNotificationPreferences(normalizeNotificationPreferences(notificationData.preferences));
           } else {
             setNotificationPreferences(createDefaultNotificationPreferences());
           }
@@ -301,6 +323,10 @@ export function useSettingsController({ isOpen, initialTab }: UseSettingsControl
     void refreshProviderAuthStatuses();
   }, [initialTab, isOpen, loadSettings, refreshProviderAuthStatuses]);
 
+  useEffect(() => {
+    setNotificationSoundEnabled(notificationPreferences.channels.sound);
+  }, [notificationPreferences.channels.sound]);
+
   useEffect(() => {
     localStorage.setItem('codeEditorTheme', codeEditorSettings.theme);
     localStorage.setItem('codeEditorWordWrap', String(codeEditorSettings.wordWrap));

src/components/settings/types/types.ts

@@ -1,4 +1,5 @@
 import type { Dispatch, SetStateAction } from 'react';
+
 import type { LLMProvider } from '../../../types/app';
 import type { ProviderAuthStatus } from '../../provider-auth/types';
 
@@ -29,6 +30,7 @@ export type NotificationPreferencesState = {
   channels: {
     inApp: boolean;
     webPush: boolean;
+    sound: boolean;
   };
   events: {
     actionRequired: boolean;

src/components/settings/view/tabs/NotificationsSettingsTab.tsx

@@ -1,5 +1,8 @@
-import { Bell, BellOff, BellRing, Loader2 } from 'lucide-react';
+import { Bell, BellOff, BellRing, Loader2, Play, Volume2 } from 'lucide-react';
 import { useTranslation } from 'react-i18next';
+
+import { Button } from '../../../../shared/view/ui';
+import { playChatCompletionSound } from '../../../../utils/notificationSound';
 import type { NotificationPreferencesState } from '../../types/types';
 
 type NotificationsSettingsTabProps = {
@@ -82,6 +85,54 @@ export default function NotificationsSettingsTab({
         )}
       </div>
 
+      <div className="space-y-4 rounded-lg border border-border bg-card p-4">
+        <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
+          <div className="space-y-1">
+            <div className="flex items-center gap-2">
+              <Volume2 className="h-4 w-4 text-blue-600" />
+              <h4 className="font-medium text-foreground">
+                {t('notifications.sound.title', { defaultValue: 'Sound' })}
+              </h4>
+            </div>
+            <p className="text-sm text-muted-foreground">
+              {t('notifications.sound.description', {
+                defaultValue: 'Play a short tone when a chat run finishes.',
+              })}
+            </p>
+          </div>
+
+          <label className="flex shrink-0 items-center gap-2 text-sm text-foreground">
+            <input
+              type="checkbox"
+              checked={notificationPreferences.channels.sound}
+              onChange={(event) =>
+                onNotificationPreferencesChange({
+                  ...notificationPreferences,
+                  channels: {
+                    ...notificationPreferences.channels,
+                    sound: event.target.checked,
+                  },
+                })
+              }
+              className="h-4 w-4"
+            />
+            {t('notifications.sound.enabled', { defaultValue: 'Enabled' })}
+          </label>
+        </div>
+
+        <Button
+          type="button"
+          variant="outline"
+          size="sm"
+          onClick={() => {
+            void playChatCompletionSound({ force: true });
+          }}
+        >
+          <Play className="h-4 w-4" />
+          {t('notifications.sound.test', { defaultValue: 'Test sound' })}
+        </Button>
+      </div>
+
       <div className="space-y-4 bg-card border border-border rounded-lg p-4">
         <h4 className="font-medium text-foreground">{t('notifications.events.title')}</h4>
         <div className="space-y-3">