Evidence trail for the rc_* mapping in the prior commit: real value_counts() over the 7 MI report-card columns, confirming the 5-value grade vocabulary and that 'Achievement'/'Safeguarding standards' match by exact string only (no legacy OEIF column accidentally consumed). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0146VHeLAWjDVE2B5uU67jCB