Fix: settings window lifecycle to allow OBS system tray minimization

[mrTomatolegit]

• Correctly destroy settings window using WA_DeleteOnClose and destructor cleanup.
• Simplify menu callback to focus or recreate window.

Resolves #87
Resolves #62

[campbellwmorgan]

Hi, Thank you so much for submitting this PR. Codewise I think it looks good, but I'll have to clone in locally and test it before merging which I hope to do be able to do some time this week.

It seems like you've used spaces for indentation instead of tabs here and the code style isn't quite the same (ie scope { should appear below the text (ie if...\r{, not if ... { ). I appreciate that it is hard to know this as we haven't explicitly adopted a styleguide or have any editor guidance. [Edit] Sorry I realise that actually that you've done it correct to the CLang format that we added. Leave that as it is, but please use tabs instead of spaces.

Would you mind conforming your changes to that and then if the testing works out OK, i'll happily merge.

Thanks again

[campbellwmorgan]

@mrTomatolegit Thanks a lot for doing that so quickly. Will approve and merge as soon as I get a chance to test it properly :)

[campbellwmorgan]

This works great. Thank you very much for the contribution.