Add a new CLI application (`cmd/cli/`) that generates command-line interface commands from the API swagger specification. Includes:
- Main CLI entry point with command parsing and execution
- Code generator that reads swagger.json and generates typed command handlers
- Makefile targets (`gen-cli`, `build-cli`) for generating and building the CLI
- GitHub Actions workflow to build cross-platform CLI binaries (linux/amd64, linux/arm64)
