This makes it clearer which files contain React components, and which do not.

# Important Notes
The main things that should be tested to confirm that this did not break anything is the two files containing Tailwind classes:
- Shortcuts ("delete" in context menu should still be red. `text-delete` is used elsewhere though, so this should not be broken either way)
- Indentation of directory contents (multiple levels)
Many of the others should more or less be self-testing:
- `index.tsx` -> `index.ts` would break the entire app if not handled properly
- `hooks.tsx` contains `useNavigate` which would break routing if absent, and `useToastAndLog` which would break most  toast notifications.
- `http.tsx` contains the HTTP client which would break all backend requests
- `useRefresh.tsx` would... break login and logout if it was broken I guess