Build outputs to dist/modes/interactive/theme/*.json but workflow
expected dist/theme/*.json. The copy-binary-assets script creates
dist/theme/ but CI never invokes it.
Fixes v0.18.0 release failure:
https://github.com/badlogic/pi-mono/actions/runs/20082833642
- Add build:binary script for Bun compilation
- Add paths.ts for cross-platform asset resolution (npm/bun/tsx)
- Add GitHub Actions workflow for automated binary releases
- Update README with installation options
Based on #89 by @steipete