Add Greek (el) localization

[Camthalion77]

Summary

This pull request adds complete Greek (el) localization support to PureMac.

Changes

• Translated all 857 interface strings into Greek.
• Localized 7 InfoPlist strings and the Finder service.
• Added Greek to the application language selector.
• Registered Greek resources in the Xcode project.
• Preserved localization keys and formatting placeholders.

Validation

• Verified localization key and placeholder consistency.
• Successfully built the application for Intel macOS 13.0+ using Xcode.
• Verified the resulting application's code signature.

Thank you for considering Greek language support for PureMac!