After some search in out forum I found the solution is:
In the ~/.kde/share, create a folder name: templates, and put your file to this folder so it will appear in your righ-click.
So I create 3 file, names: "app.yaml", "appeinge.go", "main.go". And test the right-click, well..I only see "appeinge.go" appear, not sure why I can see "app.yaml" and "main.go"!