fix(release): prepend container-image header to release notes

[richardmhope]

Why: the IcebergEBS v0.1.0-beta.1 release notes didn't reference the published image at all, and looked nothing like the sibling IcebergTTX releases. Root cause: release.yml's Create GitHub Release step used only --generate-notes, whereas IcebergTTX's step prepends a terse container-image header via --notes-file.

This mirrors IcebergTTX so the family's releases read as one system — a 3-line header (image ref by its normalized OCI tag + a pointer to docs/RELEASING.md) above the auto-generated "What's Changed":

Container image published to GHCR — SBOM + SLSA provenance attested, cosign-signed:

    ghcr.io/icebergai/icebergebs:<tag>

Pull, verify (cosign / attestation), and deploy instructions: docs/RELEASING.md.

• The image tag comes from steps.meta.outputs.version (docker/metadata-action's normalized SemVer — no v), passed through an env: var rather than interpolated into the shell (zizmor-clean).
• I already re-edited the existing v0.1.0-beta.1 release body to this format by hand; this makes every future release match automatically.

The other visible difference — beta.1's huge full-history "What's Changed" — is inherent to it being the first release (--generate-notes has no prior tag to diff against) and self-corrects at beta.2, which will produce a short compare/… list like IcebergTTX. No change needed for that.

🤖 Generated with Claude Code

[icebergai-review-bot]

IcebergAutoReview

Verdict: approve

The release workflow correctly prepends the container image reference while retaining generated notes. The normalized metadata version matches the published SemVer tag, shell inputs are safely passed through environment variables, and existing security/pinning conventions remain intact.

Findings

• No blocking findings.

Validation

• Inspected the complete main...HEAD diff and surrounding release workflow
• Verified clean ancestry and single-file scope
• git diff --check main...HEAD passed
• timeout 120s actionlint .github/workflows/release.yml passed
• Bash syntax probe for the modified release script passed
• Confirmed via gh release create --help that supplied notes are prepended when --generate-notes is used

Residual risks / optional notes

• The tag-triggered publishing step was not executed locally because it would create external release artifacts; current-head CI provides the broad validation baseline.

Automated review by Codex 51e043bfd03a using IcebergAutoReview.