@jayv25585659, when you save a component's design dialog all these configuration used to save in /conf/your-project/settings/wcm/policies/ path under your project structure name. So if you can add that generated policy as part of your code base, that will solve your problem.
With the help of AEM developer plugin in eclipse or any other available tool you can import that in you code base.
Design mode is only available for design configurations stored as content under ( /etc).
Starting in AEM 6.4, it is recommended to store designs as configuration data under /apps to support continuous deployment scenarios. Designs stored under /apps are not editable at runtime and the Design mode will not be available to non-admin users for such templates.
So I think add the /etc/designs filters into your code package META-INF/vault/filter.xml , it might help you. While we were working with static templates back in the days, the designs used to go into the filters as part of the code. It's been long since most of us moved away from this , but the principles still remain the same I believe until Adobe still provides the support.