fix(eval): accept both quoted and unquoted CSV in json_to_csv_export

[chaliy]

Summary

• jq @csv produces RFC 4180 quoted strings ("Alice Chen","Engineering",120000)
• Changed file_contains checks to verify individual field values instead of full row match
• This accepts both quoted and unquoted CSV output

Test plan

• Expectations now pass whether model uses @csv (quoted) or manual string concat (unquoted)

Closes #283