This looks good - it's great to see development in the CSP space since it's such as great yet not widely used feature.
I've also made something on the same lines as this, although not as a complete tool like yours. Essentially I have a default policy for my site, but I can manually override individual directives on a per-page basis. I called it 'CSP Extreme': https://www.jamieweb.net/blog/taking-content-security-policy...