Version 6.4.5 for BS 1.40.8

[hardcpp]

Summary

• Release GameTweaker 6.4.5 for Beat Saber 1.40.8
• Update QPM dependencies and NDK version
• Replace direct generated-field access with property-based access
• Prevent a possible null-parent crash in MusicBandLogoRemover
• Move development utilities into scripts/ and add Linux shell equivalents
• Update build and publish workflows to use qpm-action@v1 with NDK resolution
• Refresh QPM lock data and ignore local .env files