Refactoring Redux code: hooks, thunks, and redux-toolkit

Most of the Redux code is this package was written years ago and has not been touched since. In that time, Redux has come a long way! The bad news is that this codebase goes against a lot of the Redux Best Practices. The good news is that the newer ways of doing things are much easier and involve a lot less boilerplate.

Some things which can be improved/changed:

• Can use createSlice which automatically creates the action creators for a reducer so that you don't need to define a bajillion constants or define basic action creator functions. This can be tackled one "slice" at a time, as Redux Toolkit is fully compatible with old/vanilla Redux.
• Can use createAsyncThunk to automatically dispatch pending, error and fulfilled actions for each asynchronous action.
• Can use useSelector and useDispatch hooks instead of the connect HOC.

I can do a lot of this myself, but I wanted to post it as a discussion first because I don't want to waste time rewriting code if it's not wanted.

The issue identifies the Redux codebase and constants.js but does not name a specific reducer, test, or entry point. Start by reviewing those areas against the linked Redux Best Practices, then clarify the intended slice or migration scope; done would require an agreed, tested modernization plan.