Instead of hacking around the version in the Node.js wrapper script,
properly pass the version at build time via SANDBOX_AGENT_VERSION env var.
Changes:
- build.rs: Generate version.rs with VERSION constant from env var
- main.rs: Use generated version constant for clap --version
- Dockerfiles: Accept SANDBOX_AGENT_VERSION as build arg
- build.sh: Pass version as second argument to Docker builds
- release.yaml: Pass version to build script during CI
- Remove version hack from sdks/cli/bin/sandbox-agent wrapper
The version is now baked into the binary during the release build,
ensuring --version reports the correct npm package version.