v0.3.0 - support new auth for firmware >= 1.18

v0.3.0: Add dual authentication support

Features:

• Implement new salt-based authentication (firmware ≥1.18) with automatic fallback to legacy method
• Add -version flag with build-time version injection
• Add GitHub Actions workflow for automated multi-platform releases

Improvements:

• Update Go to 1.25.5
• Add build documentation in README
• Package Windows, Linux and macOS builds