v0.8.0-beta

fix(ci): remove mac-x64 build, rely on Rosetta 2

Cross-compilation for Intel Mac from ARM64 runners is complex due to
VCV Rack SDK's machine architecture auto-detection. Intel Mac users
can run the ARM64 binary via Rosetta 2, which works seamlessly.

Builds now target:
- Linux x64
- Windows x64
- macOS ARM64 (Apple Silicon, works on Intel via Rosetta)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>