fix: Replace skill ordering in getIssueSkillLevel with SKILL_HIERARCHY

[oGranny]

Description:
removes an inline, locally-defined skill-level ordering array in the GitHub automation script and replaces it with the shared SKILL_HIERARCHY constant.

Related issue(s):
Fixes #1238

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[github-actions]

Hey @oGranny 👋 thanks for the PR!
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PR Checks

✅ DCO Sign-off -- All commits have valid sign-offs. Nice work!

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✅ Issue Link -- Linked to #1238 (assigned to you).

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[rwalworth]

LGTM - the change correctly replaces the inline skillLevels array with the shared SKILL_HIERARCHY constant, giving us a single source of truth for the skill ordering. I verified that SKILL_HIERARCHY contains the exact same values and is already imported. All 24 bot tests pass. Running the workflows now and will get this merged once they pass!

Congratulations on your first contribution to the Hiero C++ SDK @oGranny! 🎉 Thank you for taking the time to contribute!