release: draft from an existing tag

[HarshwardhanPatil07]

Why

The v0.1.2 tag already exists. Its initial release run failed when the Fedora-built bink binary was executed on the Ubuntu runner. A draft release was created manually for the tag and initially had no assets.

Changes

• Allow manual dispatch for an existing release tag.
• Build and verify the downloadable binary on the runner with the dependencies used by CI.
• Check release state before pushing images. Upload bink to an existing draft, create a draft when none exists, and refuse an already published release.

Verification

• Local make build-bink VERSION=v0.1.2 and ./bink version succeeded.
• Parsed the workflow YAML, checked shell syntax, and exercised draft, absent, published, and API-error paths with a mocked gh.
• The branch release run succeeded: the binary passed its version check, all three images were pushed, and bink was uploaded to the existing draft. The release remains a draft.
• The PR's container-image usage check timed out while pulling Kubernetes images; the other checks passed. Timed-out job.

The downloadable binary uses libgpgme.so.11, as did the published v0.1.1 asset. Neither runs on Fedora 44 without that library; the README documents building locally or using the container image. Cross-distribution binary packaging can be addressed separately.

Assisted-by: AI
Signed-off-by: HarshwardhanPatil07 harshpat@redhat.com