Add support for include OAuth scope

This change expands `Scope` to support include scope. I also changed the source to https://tangled.org/ngerakines.me/atproto-crates, which is where the active code actually lives now. The `url_decode` / `url_encode` can be removed if `percent-encoding` is fine to be added as dependency. Full disclosure, the change was mostly written with Claude but I reviewed the code.