feat: introduce WebSocket sync for XBoard nodes

- Implement Workerman-based `xboard:ws-server` for real-time node synchronization.
- Support custom routes, outbounds, and certificate configurations via JSON.
- Optimize scheduled tasks with `lazyById` to minimize memory footprint.
- Enhance reactivity using Observers for `Plan`, `Server`, and `ServerRoute`.
- Expand protocol support for `httpupgrade`, `h2`, and `mieru`.

app/Models/User.php

@@ -147,6 +147,14 @@ class User extends Authenticatable
                $this->plan_id !== null;
     }
 
+    /** 
+     * 检查用户是否可用节点流量且充足
+     */
+    public function isAvailable(): bool
+    {     
+        return $this->isActive() && $this->getRemainingTraffic() > 0;   
+    }
+
     /**
      * 检查是否需要重置流量
      */