Generated a cosign keypair for v0.7 OCI signing.
- bluebuild/cosign.pub committed alongside the recipe
- cosign.key stored on operator workstation only (chmod 600)
- COSIGN_PRIVATE_KEY Forgejo Actions secret set to the same key
- Workflow stages the secret to bluebuild/cosign.key at build time
(chmod 600), where the BlueBuild signing module picks it up
- .gitignore guards against any cosign.key accidental commit
- Restored the type:signing module in recipe.yml
The 'stage-keys' COPY step in BlueBuild's generated containerfile
fails without cosign.pub adjacent to recipe.yml even when
type:signing is removed; re-add the module + provide real keys.
