fix: 资产信息接口 device_realtime 字段返回固定假数据，避免前端因 nil 报错

Gateway 同步接口尚未对接，临时为设备类型资产返回 mock 数据，
后续对接后搜索 buildMockDeviceRealtime 替换为真实数据

internal/handler/app/client_asset.go

@@ -185,6 +185,11 @@ func (h *ClientAssetHandler) GetAssetInfo(c *fiber.Ctx) error {
 		BoundDeviceName:     resolved.Asset.BoundDeviceName,
 	}
 
+	// TODO: Gateway 同步接口对接后，替换为真实设备实时数据
+	if resp.AssetType == "device" {
+		resp.DeviceRealtime = buildMockDeviceRealtime()
+	}
+
 	return response.Success(c, resp)
 }
 
@@ -586,3 +591,45 @@ func packageStatusName(status int) string {
 		return "未知"
 	}
 }
+
+// buildMockDeviceRealtime 构建设备实时状态假数据
+// TODO: Gateway 同步接口对接后移除此函数，改为调用 Gateway 接口获取真实数据
+func buildMockDeviceRealtime() *dto.DeviceRealtimeInfo {
+	onlineStatus := int64(1)
+	batteryLevel := int64(85)
+	deviceStatus := int64(1)
+	runTime := "3600"
+	connectTime := "3500"
+	rsrp := int64(-80)
+	rsrq := int64(-10)
+	rssi := "-65"
+	sinr := int64(15)
+	ssid := "JunHong-WiFi"
+	wifiEnabled := true
+	wifiPassword := "12345678"
+	ipAddress := "192.168.1.1"
+	lanIP := "192.168.1.1"
+	dailyUsage := "0"
+	maxClients := int64(32)
+	switchMode := 0
+
+	return &dto.DeviceRealtimeInfo{
+		OnlineStatus: &onlineStatus,
+		BatteryLevel: &batteryLevel,
+		Status:       &deviceStatus,
+		RunTime:      &runTime,
+		ConnectTime:  &connectTime,
+		Rsrp:         &rsrp,
+		Rsrq:         &rsrq,
+		Rssi:         &rssi,
+		Sinr:         &sinr,
+		SSID:         &ssid,
+		WifiEnabled:  &wifiEnabled,
+		WifiPassword: &wifiPassword,
+		IPAddress:    &ipAddress,
+		LANIP:        &lanIP,
+		DailyUsage:   &dailyUsage,
+		MaxClients:   &maxClients,
+		SwitchMode:   &switchMode,
+	}
+}