feat(messaging): implement optimistic updates with retry for failed messages

- Add pending/failed message status to track send state
- Implement optimistic UI: show message immediately, update on server response
- Add retry functionality for failed messages via tap-to-retry
- Change send button from icon to text "发送" for clarity
- Add MessageSendService with temp ID generation to prevent collisions

feat(notification): add JPush notification deduplication and clear on tap

- Deduplicate notificationArrived events from dual JPush/vendor channels
- Clear all notifications on tap (QQ-style behavior)

feat(post): add client-side idempotency key for post creation

- Generate client_request_id per publish intent to prevent duplicates on retry
- Pass idempotency key through to postService and voteService

app/_layout.tsx

@@ -128,6 +128,13 @@ function NotificationBootstrap() {
         console.log('[NotificationBootstrap] JPush notification:', message.notificationEventType, message);
         if (message.notificationEventType !== 'notificationOpened') return;
 
+        // 点击任意一条通知即清除通知栏所有通知（与 QQ 一致：点一条清全部）
+        // JPush 的 notificationOpened 在通知被点击时触发，此时清除系统通知栏中
+        // 本应用的所有通知，避免用户需要逐条点击消除。
+        systemNotificationService.clearAllNotifications().catch((error) => {
+          console.warn('[NotificationBootstrap] clearAllNotifications failed:', error);
+        });
+
         const extras = message.extras || {};
         const notifType = extras.notification_type || message.notificationType;