v0.6.7 - under the hood improvements

🚀 What's Changed in v0.6.7

⚡ CLI & User Flow

• Prompt-First Execution: Available updates are presented immediately. If cancelled (N), the tool exits cleanly (exit 0) without prompting for sudo credentials.
• UI cleanup
• Reboot Detection: Automatically detects /run/reboot-required upon upgrade completion and warns the user if core libraries (e.g., glibc) or kernel modules were updated.

🛡️ Backend & Reliability

• Atomic Cache Writing: check_backend.sh now uses atomic file replacements (os.replace) to eliminate race conditions when reading status cache from the system tray applet.
• Restored Timestamp: Re-added last_check UTC timestamps for precise "time since check" status reporting in the tray menu.
• Input Validation: Improved menu handling in debian-update-debget to handle empty inputs gracefully.

📦 Packaging & Standards

• Debian Policy § 10.9 Compliance: Added --root-owner-group to dpkg-deb in build_deb.sh for rootless, warning-free package creation.