* CI: duplicate-PR check and a required 'Changes a default' line (Refs #6439)
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* PR checks: enforce the defaults line only on PRs opened from 2026-10-25 (Refs #6439)
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>