feat(posts): filter posts by blocked users

Add functionality to filter out posts from blocked users in post listing endpoints. Includes a new `IsBlockedBatch` method for efficient batch checking of blocked relationships and `is_blocked` field in API responses when viewing a blocked user's posts.

internal/service/push_service.go

@@ -482,6 +482,7 @@ func (s *pushServiceImpl) pushSystemNotificationViaWebSocket(ctx context.Context
 		"type":       string(notification.Type),
 		"title":      notification.Title,
 		"content":    notification.Content,
+		"is_read":    notification.IsRead,
 		"extra":      map[string]any{},
 		"created_at": notification.CreatedAt.Format("2006-01-02T15:04:05Z07:00"),
 	}