Release script should wait for initial PR checks to appear

[gaelic-ghost]

Summary

The maintain-project-repo standard release flow can fail immediately after opening/updating a release PR when GitHub has not reported checks yet.

In gaelic-ghost/SpeakSwiftlyServer, running:

sh scripts/repo-maintenance/release.sh --mode standard --version v4.3.8 --skip-version-bump

successfully validated locally, pushed the release branch, pushed the v4.3.8 tag, and opened/updated the release PR, but then exited with a failure because no PR checks had appeared yet.

Observed behavior

The release script reached the PR check gate before GitHub Actions had attached the workflow run to the PR and reported:

ERROR: no checks reported for pull request #42.

The workflow run appeared shortly afterward and continued normally. This happened repeatedly on the same release branch, so it looks like a race between PR creation/update and the first populated statusCheckRollup/checks response.

Expected behavior

The release flow should treat "no checks reported yet" as a pending/settling state for a bounded window, not as an immediate hard failure.

A likely fix is to poll for initial check discovery separately before evaluating pass/fail status, with a clear timeout message if checks never appear.

Context

• Skill/tooling source: productivity-skills:maintain-project-repo
• Generated script: scripts/repo-maintenance/release.sh
• Example downstream repo: gaelic-ghost/SpeakSwiftlyServer
• Example PR: release: prepare v4.3.8 SpeakSwiftlyServer#42
• Example Actions run that appeared after the script failed: https://github.com/gaelic-ghost/SpeakSwiftlyServer/actions/runs/24943072416