* Move threadpool initialization and `OnExitGame` registration from `SaveManager::Init` to SM's constructor.
Comment on `Init` to mention it's not an initializer for `SaveManager`.
Added check for `SaveManager::SaveSection` to prevent firing a save worker if the game is already exited from a reset.
* Removed `IsSaveLoaded` check in favor of another `ThreadPoolWait()` at the start of `SaveManager::Init()`.