Microsandbox provider is embedded with broader compute support

The Microsandbox remote execution provider is now embedded in the once-cli binary for Linux and Apple Silicon macOS, so once exec --remote --compute microsandbox works without installing a separate package. Intel macOS targets stay on the existing unsupported path instead of hitting a build error, and remote Daytona execution is invoked through its HTTP API rather than shelling out, making remote runs more reliable.