fix(#837): Fix the 'Check for updates' alert dialog-box

[jyshnkr]

Root Cause: A timing race condition where Sparkle's update controller is initialized with startingUpdater: true at t=0.1s, but the app isn't fully activated until t=0.3s. The dialog appears before the app has proper window focus, making it unresponsive.

Changes:

• Change startingUpdater to false and manually call updater.start() after the app is fully initialized (with a ~0.5s delay), ensuring the app is properly activated and can receive input events before any Sparkle dialogs appear.

[nbelles]

I'm also experiencing this issue. Bumping for visibility

[stonerl]

@nbelles Sorry for hijacking this PR maybe you want to give https://github.com/stonerl/Thaw a try