Typing fixes

[joooooooooe-star]

and more fixes

[redshadowhero]

I'd really like you to break this into 2+ PRs:

• One with typing annotations only — this is straightforward and easy to reason about
• One with logic changes — the bulk of the logic changes you're making are isolated under the character module, so that becomes easier to reason about

This PR is going to drag on for a while as-is, and not because I as a reviewer or you as a submitter are doing anything wrong, but for one very simple reason: the change domain is very broad. I can review python typing, structure, language features etc just fine, but all at once it becomes harder to reason about.