refactor: unify Linux window management with macOS logic and remove h…

[eedali]

…ardcoded screen offsets

Description

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Fixes #

Type of Change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• UI/UX improvement (visual changes or enhancements)
• Documentation update

Screenshots / Video

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Checklist

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• I have tested my code locally and it works flawlessly.
• I am strictly sure that my changes DO NOT break KoBar's "Ghost Window" (transparent window) and click-through logic.
• I have added necessary descriptions and comments to my code.
• My code does not generate any new warnings or errors in the console.