Allowing inline scripts in templates would be a security nightmare, so it isn’t allowed. Injecting a custom controller for the template widget might be considered at some point, but probably not in the next weeks/months.
In that case you should clone the GitHub repository in your static files (conf/html), make a branch, modify the source and go to your modified version at /static/habpanel/web/index.html.
And if your change would be useful to others, why not submit a pull request!