Stabilize release GHCR distribution by inlining build job on ubuntu-latest

[Copilot]

[Workflow] On Release Published intermittently failed at Distribute / Docker Build and Push (GHCR) (job 78681796774) before any actionable step logs were emitted from the build step. This change removes the failing execution path while preserving release image build/push behavior.

• What changed

  • Replaced reusable workflow invocations in .github/workflows/on_release_published.yml:
    • release-distribute-ghcr
    • release-distribute-ghcr-prerelease
  • These jobs now run directly on ubuntu-latest with explicit steps instead of uses: webgrip/workflows/...docker-build-and-push-ghcr.yml@main.

• Behavior preserved

  • Same Docker context/file/platforms/build args.
  • Same release tag semantics (version and latest for stable; version only for prerelease).
  • Same GHCR/Docker credentials wiring via env (GHCR_*, DOCKER_*).

• Operational impact

  • Keeps the GHCR build/push logic (same composite action), but avoids the unstable reusable-workflow + runner path that caused the release job to hang/fail.

- uses: ./.github/composite-actions/docker-build-push-ghcr
  with:
    docker-context: "ops/docker/${{ needs.parse-release-tag.outputs.image }}"
    docker-file: "Dockerfile"
    platforms: "linux/amd64,linux/arm64"
  env:
    GHCR_USERNAME: ${{ github.actor }}
    GHCR_TOKEN: ${{ secrets.GITHUB_TOKEN }}