fix(ci): skip upstream release jobs on fork - #6

Issue for this PR

Closes #5

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

The fork's dev push leaves generate queued on an unavailable Blacksmith runner. The publish job also queues because its always() condition runs after the upstream-only build jobs are skipped. Opening an issue or PR queues upstream triage and duplicate-check jobs on the same unavailable runner. This PR limits those jobs and the GitHub Action release job to anomalyco/opencode. On the fork, they skip before requesting a runner. Upstream behavior is unchanged.

How did you verify your code works?

• Parsed the three workflow files and checked the diff for whitespace errors.
• Confirmed the merged fork dev run has generate and publish queued on Blacksmith, while Linux tests, typecheck, and Nix evaluation use GitHub runners.
• The PR checks will verify that the new conditions are accepted by GitHub Actions.

Screenshots / recordings

No UI change.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR