Using attw with peer typescript

[43081j]

We can't reintroduce attw until we can run it without pulling it's own typescript version in.

Currently it has a dependency on a specific version rather than using a peer because it depends on private typescript APIs.

So we can decide one of two things:

• get it to work against any given typescript version and gracefully fail if those private APIs are different
• don't use attw, and just rely on the static checks publint does