Function build_deploy_manifest 

fn build_deploy_manifest(
    manifest_path: &Path,
    config: &Config,
    clean: bool,
) -> Result<()>

Build every package referenced by a top-level robonix_manifest.yaml. Two phases:

1. fetch — path: entries already on disk; url: entries get git clone --depth 1 into rbnx-boot/cache/<name>/ (idempotent — skipped when the cache dir already exists).
2. build — for each resolved package, run its build.sh.

rbnx boot deliberately does NOT do either; it just verifies both phases happened (warns + remediates if not). This lets “fetch → build” be a controlled offline step the user can run when they have network / time, then rbnx boot is a fast, online-optional bring-up.