Create workflows locally, Save them and make copies as you need them or use them as sub workflows
Create your own template service which will allow you to see your templates under the templates field in n8n, This is normally used by embed customers.
You wouldn’t create templates in the docker image, If you were after option 3 where you use your own template service you would need to build your own api service that returns them following the endpoints and responses listed on the templates page.
We don’t have an example service for this as we found different embed customers would handle it in different ways depending on what they currently use in their environment.