custom categories templates
a GUI to make custom event templates would look like the regular config for an event, but there would be a button to "save as a new category template". hence, custom categories would have CRUD capabilities. also, we would need a way to list our templates, but not change the common base templates. edit would be the same screen than creating, and delete would propose confirmation before deleting several custom templates.
would require a backend API too.
this feature can come after the first milestone as an improovement.