feat: add notifyOnSubtasks setting to control subtask notifications (#227)

* feat: add notifyOnSubtasks setting to control subtask notifications

- Add notifyOnSubtasks toggle in NotificationSettings (moved to general section)
- Update useEventStream.ts to skip notifications for subtasks when disabled
- Add server-side push notification control for subtasks
- Update UI store, persistence, and desktop settings types

* feat: apply notifyOnSubtasks across web push + desktop notifications

---------

Co-authored-by: Jovines <jovines@qq.com>

packages/ui/src/hooks/useEventStream.ts

@@ -150,6 +150,7 @@ export const useEventStream = () => {
   const { checkConnection } = useConfigStore();
   const nativeNotificationsEnabled = useUIStore((state) => state.nativeNotificationsEnabled);
   const notificationMode = useUIStore((state) => state.notificationMode);
+  const notifyOnSubtasks = useUIStore((state) => state.notifyOnSubtasks);
   const fallbackDirectory = useDirectoryStore((state) => state.currentDirectory);
 
   const activeSessionDirectory = React.useMemo(() => {
@@ -1310,6 +1311,17 @@ export const useEventStream = () => {
 	            const shouldNotify = notificationMode === 'always' || visibilityStateRef.current === 'hidden';
 
 	            if (shouldNotify) {
+	              // Check if this is a subtask and if we should notify for subtasks
+	              if (!notifyOnSubtasks) {
+	                const sessions = useSessionStore.getState().sessions;
+	                const session = sessions.find(s => s.id === sessionId);
+	                const isSubtask = session && 'parentID' in session && Boolean((session as { parentID?: string }).parentID);
+	                if (isSubtask) {
+	                  // Skip notification for subtasks
+	                  return;
+	                }
+	              }
+
 	              const notifiedMessages = notifiedMessagesRef.current;
 
 	              if (!notifiedMessages.has(messageId)) {
@@ -1610,6 +1622,7 @@ export const useEventStream = () => {
     currentSessionId,
     nativeNotificationsEnabled,
     notificationMode,
+    notifyOnSubtasks,
     addStreamingPart,
     completeStreamingMessage,
     updateMessageInfo,
@@ -2095,6 +2108,7 @@ export const useEventStream = () => {
     loadSessions,
     maybeBootstrapIfStale,
     resyncMessages,
-    scheduleSoftResync
+    scheduleSoftResync,
+    notifyOnSubtasks,
   ]);
 };