After doing some testing, I'm confident I believe that the Zone Ventilation column in the Zone Component Load Summary report will show loads for outdoor air entering the zone or air exhausted to outdoors from leaving the zone that are defined by zone ventilation objects like ZoneVentilation:DesignFlowRate. These are meant to model natural ventilation or zone intake / exhaust fans.

The outside ventilation air that you defined using the DesignSpecification:OutdoorAir object will pass through the individual fan unit, which is an HVAC object and not a zone ventilation object. Notice As such, the load of cooling or heating that there is a outdoor air should be included in the Cooling Peak ConditionsHVAC Equipment Loads and Heating Peak Conditions table for each zone that lists the outdoor air condition and zone air condition at the time of peak load that occurs on the respective design day. EnergyPlus uses that information, the outside ventilation air you specify, and the loads generated for the zone to calculate the HVAC capacity that is required. column.

You can refer to a related question here and the Engineering Reference documentation about the Zone Component Load Summary report here for more details.