feat: enable artifacts for google/gemma-4-31B-it (#2399)
Add "supportsArtifacts": true to the gemma-4-31B-it entry in both
prod.yaml and dev.yaml so the artifacts side panel is enabled for it.
Claude-Session: https://claude.ai/code/session_01KgHyoQXKBqhZpHykjep7RA
Co-authored-by: Claude <noreply@anthropic.com>