fix(ofsted): badge and compare read the grade still in force

Search badges date a grade by the inspection that awarded or confirmed it (ofsted_grade_date) and say 'Inspected · year' when the latest inspection gave no grade. ofstedDisplay's kinds become graded / confirmed / no_overall_grade, read from current_grade rather than a carried-forward overall_effectiveness. lib/ofstedStatus.ts holds the two sentences the school and compare pages share.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

nextjs-app/lib/compareLogic.ts

@@ -100,9 +100,8 @@ export function summariseReportCard(ofsted: OfstedInspection): ReportCardSummary
 
 export type OfstedDisplay =
   | { kind: 'none' }
-  | { kind: 'graded'; grade: number; gradeLabel: string; carriedForward: false }
-  | { kind: 'carried_forward'; grade: number; gradeLabel: string; carriedForward: true }
-  | { kind: 'transitional' }
+  | { kind: 'graded' | 'confirmed'; grade: number; gradeLabel: string; gradeDate: string | null }
+  | { kind: 'no_overall_grade' }
   | { kind: 'report_card'; summary: ReportCardSummary };
 
 export function ofstedDisplay(
@@ -116,19 +115,19 @@ export function ofstedDisplay(
     return { kind: 'report_card', summary: summariseReportCard(ofsted) };
   }
 
-  const grade = ofsted.overall_effectiveness;
-  const gradeLabel = grade != null ? OFSTED_LEGACY_GRADES[grade] : undefined;
-  if (grade == null || gradeLabel === undefined) {
-    if (ofsted.inspection_date) {
-      return { kind: 'transitional' };
-    }
-    return { kind: 'none' };
+  // The grade still in force (backend: fact_ofsted_latest), never one carried
+  // past a later inspection that gave none.
+  const current = ofsted.current_grade;
+  const gradeLabel = current ? OFSTED_LEGACY_GRADES[current.grade] : undefined;
+  if (current && gradeLabel !== undefined) {
+    return {
+      kind: current.basis === 'confirmed' ? 'confirmed' : 'graded',
+      grade: current.grade,
+      gradeLabel,
+      gradeDate: current.date,
+    };
   }
-
-  if (ofsted.grade_source === 'ungraded_carried_forward') {
-    return { kind: 'carried_forward', grade, gradeLabel, carriedForward: true };
-  }
-  return { kind: 'graded', grade, gradeLabel, carriedForward: false };
+  return ofsted.latest_visit ? { kind: 'no_overall_grade' } : { kind: 'none' };
 }
 
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