Refresh UI and improve Finder automation

• Restyle the main, settings, and credential setup views with reusable glass-style components
• Improve the AppleScript DMG path by explicitly requesting and mapping Finder Automation permission states before layout work begins, with clearer user-facing errors
• Improved log/stage presentation, and updated window sizing
• Add app language selection backed by AppleLanguages, plus new German, French, and Italian localizations
• Update the README and screenshots to document the new UI and automation behavior

App for macOS 14+ and notarized

• App is notarized by Apple
• Improve workflow messaging with concise status updates
• Introduces a new mode to use the node tool create-dmg when installed, collapsing the AppleScript DMG build sequence into a single buildDMG stage, while keeping the original AppleScript flow as automatic fallback
• Fix concurrency/sendability warnings in the Xcode project
• Minor UI/default-setting tweaks (fixed main window/sidebar sizing and default output folder on Desktop)
• Xcode project requires Xcode 16+