Mirror signing helpers
make-thin-v1.sh: builds thin bundle v1, computes checksums, optional DSSE+TUF signing whenSIGN_KEYis set, and runs verifier.sign_thin_bundle.py: signs manifest (DSSE) and root/targets/snapshot/timestamp JSON using an Ed25519 PEM key.verify_thin_bundle.py: checks SHA256 sidecars, manifest schema, tar determinism, and manifest/index digests.ci-sign.sh: CI wrapper. SetMIRROR_SIGN_KEY_B64(base64-encoded Ed25519 PEM) and run; it builds, signs, and verifies in one step.verify_oci_layout.py: validates OCI layout/index/manifest and blob digests whenOCI=1is used.
Artifacts live under out/mirror/thin/.