fix: ensure window closes even if cleanup fails

[MatrixNeoKozak]

The previous implementation for closing the application relied on a single promise from executeJavaScript without a fallback handler. If the cleanup operations failed, the then() block was not guaranteed to execute, leading to the application becoming unresponsive and unable to close. This change adds a catch() block to ensure the window closes regardless of whether the cleanup operations complete successfully or fail. Closes #1

[ollm]

Thanks for your fix, I have merged it into the master branch.

Previously, even if an error occurred during the execution of these functions, pressing the close button again should have forced the app to close.