Fix #23: JWT storage consistency across all Flutter apps

- siro_admin: added FlutterSecureStorage write alongside GetStorage
- siro_service: added FlutterSecureStorage write in login + guest JWT flows
- siro_rider: added FlutterSecureStorage write in guest + token-refresh flows
  (full-credential login already wrote to both)
- siro_driver: already wrote to both (no change needed)
- All apps now write JWT to both GetStorage and FlutterSecureStorage

siro_admin/lib/controller/functions/crud.dart

@@ -48,6 +48,7 @@ class CRUD {
       final jwt = decodedResponse1['jwt'];
       Log.print('jwt: ${jwt}');
       await box.write(BoxName.jwt, X.c(X.c(X.c(jwt, cn), cC), cs));
+      await storage.write(key: BoxName.jwt, value: X.c(X.c(X.c(jwt, cn), cC), cs));
       // await AppInitializer().getKey();
     }
   }