Stop treating Firecracker, kernels, modules, and guest images as tracked source files. Source checkouts now resolve runtime assets from ./runtime, while installed binaries keep using ../lib/banger.
Add a small runtimebundle helper plus runtime-bundle.toml so make can bootstrap, package, and install a runtime bundle with checksum validation. Update the shell helpers and daemon path hints to fail clearly when the bundle is missing instead of assuming repo-root artifacts.
This removes the tracked runtime blobs from HEAD in favor of an ignored local runtime/ tree. Verified with go test ./..., make build, bash -n on the shell helpers, make -n install, and a temporary package/fetch smoke test. The manifest URL/SHA still need a published bundle before fresh clones can bootstrap, and history rewrite remains a separate rollout step.
