feat(redux): Rename all Redux slices and store keys to match file names for clarity

- Renamed all slice names (createSlice `name` attribute) to match their file names (e.g. loopChartSlice, authSlice, kueDataSlice etc.)
- Updated `store.ts` to register each reducer with consistent key names (e.g. state.loopChartSlice instead of state.loopChart)
- Adjusted all `useSelector` and Redux state accesses across the codebase
- Improves maintainability, searchability and consistency across files and Redux DevTools

components/main/settingsPageComponents/GeneralSettings.tsx

@@ -15,7 +15,7 @@ import { fetchSystemSettingsThunk } from "../../../redux/thunks/fetchSystemSetti
 const GeneralSettings: React.FC = () => {
   const dispatch = useDispatch<AppDispatch>();
   const systemSettings = useSelector(
-    (state: RootState) => state.systemSettings
+    (state: RootState) => state.systemSettingsSlice
   );
 
   const { isAdminLoggedIn, logoutAdmin } = useAdminAuth(true);