How to replace Flutter's deprecated Radio groupValue and onChanged with RadioGroup

Radio.groupValue and Radio.onChanged were deprecated after Flutter 3.32 and RadioGroup shipped in 3.35. A step-by-step migration for Radio, RadioListTile and CupertinoRadio, why dart fix cannot do it for you, and the generic type-inference trap that silently renders a migrated radio disabled. Verified on Flutter 3.44.2 stable.